43 results on '"Dong Hwan Cho"'
Search Results
2. The Impact of Social Entrepreneurship on Sustainability: For Public Organizations
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Won Seok Bang and Dong Hwan Cho
- Subjects
General Earth and Planetary Sciences ,General Environmental Science - Published
- 2021
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3. Multiple Case Studies on the Critical Success Factors of Internet Banks: Implications for Korean Market.
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Dong Hwan Cho and Jin Hyuk Hong
- Published
- 2011
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4. Factors Affecting the Turnover Intentions of Small and Medium Construction IT Workers.
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Dong Hwan Cho and Haeng Nam Sung
- Published
- 2011
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5. A Study on the Influence Relationship between Creating Shared Value, Product Quality, Innovation, and Competitive Advantage
- Author
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Won Seok Bang and Dong Hwan Cho
- Subjects
media_common.quotation_subject ,General Earth and Planetary Sciences ,Quality (business) ,Product (category theory) ,Business ,Creating shared value ,Competitive advantage ,Industrial organization ,General Environmental Science ,media_common - Published
- 2021
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6. Impact of e-Business initiatives on firm value.
- Author
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Ho Geun Lee, Dong Hwan Cho, and Seong Chul Lee
- Published
- 2002
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7. Assessment of Settlement Profile Caused by Underground Box Structure Installation with an Artificial Neural Network Model
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Dong Hwan Cho, Jun Kyung Park, Jeongho Oh, and Sharif Hossain
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Empirical equations ,021110 strategic, defence & security studies ,Settlement (structural) ,Mechanical Engineering ,0211 other engineering and technologies ,Artificial neural network model ,Excavation ,02 engineering and technology ,Ground settlement ,Physics::Geophysics ,Geotechnical engineering ,Geology ,021101 geological & geomatics engineering ,Civil and Structural Engineering ,Ground movement - Abstract
Various empirical equations have been proposed to predict the ground settlement profile caused by the excavation of conventional circular tunnels. However, ground movement for the underground box structure has not been fully studied. In this study, ground settlement induced by underground box installations is investigated using two-dimensional finite element analyses. A new formulation to assess the settlement profile applicable to underground box structure is proposed based on parametric analyses of the changes in ground condition, geometric condition of structure, and construction conditions. This paper also presents a method to predict the maximum surface settlement around an underground box structure with artificial neural networks (ANNs), taking into account nine input variables that have direct physical significance. A MATLAB-based multi-layer back propagation neural network model is developed, trained, and tested with parameters obtained from numerical analyses. The maximum settlement from the ANN model, in conjunction with a new formulation to construct the settlement profile, turns out to be promising, by predicting a settlement profile compatible with field measurement data.
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- 2018
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8. Effects of Thermal Stabilization and Electron Beam Irradiation on the Characteristics of Lignin Extracted from Black Liquor
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Won Ho Park, Oh Hyeong Kwon, Dong Hwan Cho, Dae Kyun Hwang, and Jeong Ho Kim
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0106 biological sciences ,Radiation ,Materials science ,020209 energy ,02 engineering and technology ,Condensed Matter Physics ,01 natural sciences ,Electron beam irradiation ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,010608 biotechnology ,Thermal ,0202 electrical engineering, electronic engineering, information engineering ,Lignin ,General Materials Science ,Black liquor - Abstract
In the present work, lignin extracted from black liquor, which is industrial waste of pulp manufacturing. The extracted lignin was irradiated at various electron beam intensities from 100 to 1000 kGy. Also, the extracted lignin was thermally stabilized by heat treatment process. The characteristics of the stabilized and irradiated lignin materials were examined by means of TGA, ATR-FTIR, EA, and SEM. The ATR-FTIR result shows that both stabilized and irradiated lignin samples exhibit the decrease of characteristic absorption peaks, indicating the presence of guaiacyl and syringyl groups in the lignin structure. It reveals that the irradiation done to the ‘as-extracted’ lignin with appropriate electron beam intensity provides an efficiency as thermal stabilization of the lignin, suggesting that electron beam irradiation may apply directly to the extracted lignin, prior to carbonization the lignin without thermal stabilization process.
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- 2017
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9. RELATIVE AGE DIFFERENCE BETWEEN THE METAL-POOR GLOBULAR CLUSTERS M53 AND M92
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Sang-Gak Lee, Hyun-Il Sung, Tae Seog Yoon, and Dong-Hwan Cho
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Physics ,010504 meteorology & atmospheric sciences ,Age differences ,Photometric system ,Astronomy ,Astronomy and Astrophysics ,Astrophysics ,Horizontal branch ,01 natural sciences ,Photometry (optics) ,Space and Planetary Science ,Globular cluster ,0103 physical sciences ,Astronomy observatory ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
CCD photometric observations of the globular cluster (GC), M53 (NGC 5024), are performed using the 1.8 m telescope at the Bohyunsan Optical Astronomy Observatory in Korea on the same nights (2002 April and 2003 May) as the observations of the GC M92 (NGC 6341) reported by Cho and Lee using the same instrumental setup. The data for M53 is reduced using the same method as used for M92 by Cho and Lee, including preprocessing, point-spread function fitting photometry, and standardization etc. Therefore, M53 and M92 are on the same photometric system defined by Landolt, and the photometry of M53 and M92 is tied together as closely as possible. After complete photometric reduction, the V versus B − V , V versus V − I, and V versus B − I color-magnitude diagrams (CMDs) of M53 are produced to derive the relative ages of M53 and M92 and derive the various characteristics of its CMDs in future analysis. From the present analysis, the relative ages of M53 and M92 are derived using the Δ(B − V ) method reported by VandenBerg et al. The relative age of M53 is found to be 1.6 ± 0.85 Gyr younger than that of M92 if the absolute age of M92 is taken to be 14 Gyr. This relative age difference between M53 and M92 causes slight differences in the horizontal-branch morphology of these two GCs.
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- 2016
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10. DISCOVERY OF WHITE DWARFS IN THE GLOBULAR CLUSTERS M13 AND M22 USING HST ACS PHOTOMETRIC DATA
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Hyun-Il Sung, Tae Seog Yoon, Sang-Gak Lee, and Dong-Hwan Cho
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Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Young stellar object ,Milky Way ,White dwarf ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Bright-white ,Stars ,Space and Planetary Science ,Homogeneous ,Hubble space telescope ,Globular cluster ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
A search for hot and bright white dwarfs (WDs) in the Milky Way globular clusters M13 (NGC 6205) and M22 (NGC 6656) is carried out using the deep and homogeneous V I photometric catalog of Anderson et al. and and Sarajedini et al., based on data taken with the ACS/WFC aboard the Hubble Space Telescope (HST). V versus V − I color-magnitude diagrams (CMDs) of M13 and M22 are constructed and numerous spurious detections are rejected according to their photometric quality parameters qfit(V ) and qfit(I). In the case of M13, further radial restriction is applied to reject central stars with higher photometric errors due to central crowding. From each resultant V versus V −I CMD, sixteen and thirteen WD candidates are identified in M13 and M22, respectively. They are identified as stellar objects in the accompanying ACS/WFC images and are found to be randomly distributed across the central regions of M13 and M22. Their positions in the CMDs are in the bright part of the DA WD cooling sequences indicating that they are true WDs. In order to confirm their nature, follow-up spectroscopic observations are needed.
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- 2015
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11. NEAR-IR PHOTOMETRIC STUDY OF THE FU ORIONIS OBJECT HBC 722
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Won Kee Park, Dong Hwan Cho, Keun Hong Park, Tae Seog Yoon, Wonseok Kang, Sang Gak Lee, Hyun Il Sung, Yuna Yang, Jeong-Eun Lee, and Sunkyung Park
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Physics ,Brightness ,Stars ,Space and Planetary Science ,Infrared ,Astronomy ,Spectral energy distribution ,Astronomy and Astrophysics ,Astrophysics ,Light curve - Abstract
We present near-infrared light curves of HBC 722 after its the September 2010 outburst. We have been monitoring its near-infrared light curves since November 2010 with Korean Astronomy and Space Science Institute Infrared Camera System (KASINICS). HBC 722 exhibits large changes in optical and near-infrared brightness since its outburst. The J, H, and Ks light curves over about 2.5 years show that in all observed bands HBC 722 progressively became fainter until around April 2011, down to J �10.7, H �9.9, Ks �9.3, but it is getting brighter again. Large scatter in the obtained light curve prevents us from finding whether there is any short timescale variation as reported in other optical observations. The near-infrared color of HBC 722 is becoming bluer since its outburst. The pre-outburst Spectral Energy Distribution (SED) of HBC 722 is consistent with that of a slightly reddened Class II YSO with the exception of the extraordinary IR-excess in the far-infrared region.
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- 2013
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12. Contribution of Nociceptin to Alterations in Cerebral Blood Flow Regulation Following Postnatal Exposure to Ethanol in Rats
- Author
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Dong Hwan Cho and Won Suk Lee
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medicine.medical_specialty ,business.industry ,Dura mater ,Antagonist ,Nitric oxide ,chemistry.chemical_compound ,Nociceptin receptor ,medicine.anatomical_structure ,Blood pressure ,Endocrinology ,Cerebral blood flow ,chemistry ,Cerebral cortex ,Internal medicine ,Anesthesia ,medicine ,Autoregulation ,business - Abstract
This study aimed to investigate whether nociceptin contributes to the alterations in cerebral blood flow (CBF) regulation following postnatal exposure to ethanol in Sprague-Dawley rats. Animals received ethanol twice a day, 2 hr apart, on postnatal 6, 7 and 8 days. The changes in regional CBF (rCBF) in response to the changes in mean arterial blood pressure were determined at 4-, 8-, and 12-week of age by laser-Doppler flowmetry. Hypotension was induced by the gradual withdrawal of blood from arterial catheter, and the reversal of blood pressure was produced by the reinfusion of blood. Expression of nociceptin-like immunoreactivity was determined in dura mater and cerebral cortex using immunohistochemistry. Postnatal exposure to ethanol almost abolished the autoregulation of rCBF in all age groups. Pretreatment with nociceptin but not with [Nphe¹]nociceptin(1-13)NH₂, a selective competitive nociceptin receptor antagonist, 5 min prior to ethanol administration preserved the autoregulation of rCBF in all age groups. Postnatal exposure to ethanol markedly increased the expressions of nociceptin-like immunoreactivity in the dura mater and cerebral cortex, both of which were significantly inhibited by pretreatment with 7-nitroindazole monosodium salt as well as aminoguanidine 5 min prior to ethanol administration in all age groups. The values of arterial blood gas analysis were not significantly different from the basal levels in all groups. These results suggest that nociceptin deeply contributes to the compensatory mechanisms for the nitric oxide-dependent alterations in CBF autoregulation following postnatal exposure to ethanol.
- Published
- 2013
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13. Factors Affecting the Project Performance of Software Development Outsourcing
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Dong-Hwan Cho
- Subjects
Performance risk ,Knowledge management ,law ,business.industry ,Order (exchange) ,Vendor ,CLARITY ,Software development ,business ,Field survey ,Goal alignment ,law.invention ,Outsourcing - Abstract
SDO(Software Development Outsourcing) projects have been consistently increasing and expanding but also have many failures. In order to improve SDO performance, the factors affecting SDO performance are investigated in this study. SDO has relational risk as well as performance risk in nature, and the factors affecting the SDO performance caused by these mixed risks are drawn from the prior studies. With field survey targeted client IS personnel who experienced SDO, 214 survey questionnaires are collected and analyzed. Research results show that vendor power, client requirements certainty, goal clarity and goal alignment affect the SDO performance. However, vendor knowledge and client knowledge do not have much effect on SDO performance. The results of this study can be effectively utilized to decrease the failures of SDO and increase the possibility of success. Key Words : SDO(Software Development Outsourcing), IS Outsourcing, Project * 교신저자 : Dong-Hwan ChoTel: +82-10-3518-4793 e-mail: dhcho@gntech.ac.kr접수일 11년 09월 14일 수정일 (1차 11년 12월 05일, 2차 11년 12월 29일) 게재확정일 12년 03월 08일
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- 2012
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14. Building Trust in Smartphone Environment -Focused on the Undergraduate Students in Busan
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Dong-Hwan Cho and YooJung Choi
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Engineering ,business.industry ,User satisfaction ,Internet privacy ,Usability ,Smartphone application ,business ,Affect (psychology) - Abstract
Recently, the number of smartphone user is increasing fast, and many companies provide various mobile applications. However, not all applications remain at the smartphones, they could be deleted easily if users don`t trust them. Therefore in this study, we try to develop the model of building trust to use the smartphone applications and examines the influences of ease of use, usefulness, enjoyment on user satisfaction and trust. For this study the 221 sets of data collected, who use the smartphones, were tested against the model using PLS 2.0. The results of this study are as follows. First, perceived ease of use had an effect on usefulness and enjoyment. Second, usefulness and enjoyment had an effect on user satisfaction and trust. We can derive the factors which affect building trust in smartphone applications through this study, and provide a guideline to mobile application vendors and providers.
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- 2012
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15. Factors Affecting the Conflicts in the Outsourced Information System Development
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Dong-Hwan Cho and Hun Choi
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System development ,Project success ,Knowledge management ,Empirical research ,business.industry ,Vendor ,media_common.quotation_subject ,Information system ,Certainty ,business ,Knowledge process outsourcing ,Outsourcing ,media_common - Abstract
This study aims to investigate the major causes of conflict between clients and vendors in the outsourced IS development. A research model is established based on the prior research of IS outsourcing, system development and conflict. An empirical study was executed using 214 survey questionnaire of project teams composed of client and vendor with PASW 18.0. Research results using multiple regressions show that contract specificity, requirements certainty, objective alignment and client knowledge have negative effects on conflict. This research results will provide various implications for outsourcing project success.
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- 2010
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16. An Analysis on U-health Business Models: Focused on the Changes of Life Insurance Industry
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Dong-Hwan Cho and Seong-Ho Kim
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U healthcare ,Commerce ,New business development ,Line of business ,Life insurance ,Business ,Business model ,Value chain ,Industrial organization - Abstract
Recently major developed countries such as U.S. and EU selected u-health as future growth engine industry, and concentrated their capabilities. Major companies all around the world entered this u-health business, too. Most of the research in this field have confined their research focus on the elementary technologies for infrastructure building. This research systematically investigates u-health business models with various objectives in various sub-fields. For this purpose, the value chain of u-health industry is analyzed, and then various business model cases are explored all around the world. Finally, the future changes possible to occur in the life insurance industries are analyzed.
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- 2010
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17. Antipsychotic Effects of Quetiapine in Naturalistic Long Term Follow Up Study
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Joon Ho Ahn, In Hee Cho, Jungsun Lee, Dong Geun Lee, Chang Yoon Kim, Hae Kyung Jung, Il Kyung Jung, Se-Won Lim, Weon Jeong Lim, Dong Hwan Cho, So Young Yoo, Jong Jin Kim, Tae Young Kim, Do Hoon Kim, and Sang Hyuk Lee
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Response rate (survey) ,medicine.medical_specialty ,Dose ,Quetiapine ,medicine.medical_treatment ,Schizoaffective disorder ,medicine.disease ,High-dose ,Naturalistic study ,Psychiatry and Mental health ,Naturalistic observation ,Schizophrenia ,Internal medicine ,medicine ,Clinical Global Impression ,Original Article ,Psychiatry ,Antipsychotic ,Psychology ,Biological Psychiatry ,medicine.drug - Abstract
ObjectiveaaThis study aimed to examine the effectiveness of quetiapine and the effects of dosage relates to its effectiveness on schizophrenia and schizoaffective disorder in a naturalistic setting in Korean people. MethodsaaThis study was a 24-week, open-label, non-comparative, naturalistic study of quetiapine in patients diagnosed with schizophrenia and schizoaffective disorder according to DSM-IV. We stratified the patients into mild [(clinical global impression severity (CGI-S)
- Published
- 2010
18. Studies on the Stabilization of Rayon Fabrics for Preparing Carbon Fabrics: 2. Fast Isothermal Stabilization Processes at High Temperature
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Sung-Bong Yoon, Chae-Wook Cho, Dong-Hwan Cho, Jong-Kyoo Park, and Jae-Yeol Lee
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Materials science ,Renewable Energy, Sustainability and the Environment ,Process Chemistry and Technology ,Organic Chemistry ,Weight change ,technology, industry, and agriculture ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Oxygen ,Isothermal process ,Inorganic Chemistry ,chemistry.chemical_compound ,chemistry ,parasitic diseases ,Materials Chemistry ,Ceramics and Composites ,Thermal stability ,Composite material ,Chemical composition ,Carbon ,Phosphoric acid ,Fire retardant - Abstract
In the present study, fast isothermal stabilization processes for rayon precursor fabrics were performed at 350oC and 400oC within 3 minutes and the chemical and physical characteristics of the stabilized fabrics were investigated. In addition, rayon precursor fabrics were pre-treated with three different phosphorous-based flame retardants and then stabilized. The effect of flame retardants on the chemical composition, thermal shrinkage, weight change, thermal stability and XRD results was examined, comparing with those of the precursor fabrics. The result showed that the stabilization of rayon fabrics was most effective as the stabilization temperature was 350oC, the stabilization time was 3 min, and the pre-treatment with Phosphoric acid of 1 vol%. The carbon contents of stabilized rayon fabrics were increased with increasing stabilization temperature and time, whereas the oxygen contents were decreased. Also, it is likely that the pre-treatment with phosphoric acid plays a role in retarding the change of chemical structure of rayon fabric. The XRD result was quite consistent with the result showing the effect of phosphoric acid on the chemical composition, thermal shrinkage and weight reduction of rayon fabric. Keywords : Rayon Fabric, Isothermal stabilization process, Flame retardant, Pre-treatment, Characterization
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- 2008
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19. Effect of natural fiber surface treatments on the interfacial and mechanical properties of henequen/polypropylene biocomposites
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Seong Ok Han, Hyun Seok Lee, and Dong Hwan Cho
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Polypropylene ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Compression molding ,Modulus ,Dynamic mechanical analysis ,chemistry.chemical_compound ,chemistry ,Flexural strength ,Sodium hydroxide ,Materials Chemistry ,Fiber ,Composite material ,Natural fiber - Abstract
The surfaces of henequen fibers, which can be obtained from the leaves of agave plants, were treated with two different media, tap water and sodium hydroxide, that underwent both soaking and ultrasonic methods for the fiber surface treatment. Various biocomposites were fabricated with untreated and treated, chopped henequen fibers and polypropylene using a compression molding method. The result is discussed in terms of interfacial shear strength, flexural properties, dynamic mechanical properties, and fracture surface observations of the biocomposites. The soaking (static method) and ultrasonic (dynamic method) treatments with tap water and sodium hydroxide at different concentrations and treatment times significantly influenced the interfacial, flexural and dynamic mechanical properties of henequen/polypropylene biocomposites. The alkali treatment was more effective than the water treatment in improving the interfacial and mechanical properties of randomly oriented, chopped henequen/PP biocomposites. In addition, the application of the ultrasonic method to each treatment was relatively more effective in increasing the properties than the soaking method, depending on the treatment medium and condition. The greatest improvement in the properties studied was achieved by ultrasonic alkalization of natural fibers, which was in agreement with the other results of interfacial shear strength, flexural strength and modulus, storage modulus, and fracture surfaces.
- Published
- 2008
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20. Web 2.0 and Firms' Business Model Application
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Dong-Hwan Cho
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Web 2.0 ,Viral marketing ,business.industry ,The Internet ,Business ,Web service ,Business model ,Marketing ,computer.software_genre ,WS-Policy ,Business transformation ,computer ,Open innovation - Abstract
Recently the advent of web 2.0 era is an important trend in the business environmental change. Web 2.0 era means users` active participation, share, and openness, develop `Internet penetration into everyday life,` and change many aspects of our society. web 2.0 has been making these following changes in the socioeconomic aspects: 1) acceleration of system shift to a small quantity of multi-species production system 2) growing influence of on-line channel/information to consumers 3) various minorities` power increase in the socioeconomic sector. web 2.0 has been making these following changes in the enterprise management: 1) the pursuit of open innovation from outside 2) active employment of viral marketing through Internet 3) the pursuit of present business transformation 4) strengthening of customer communication through open dialogue. Firms must squarely look at socioeconomic changes owing to web 2.0, and utilize them as business opportunities.
- Published
- 2008
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21. Dynamic mechanical properties of natural fiber/polymer biocomposites: The effect of fiber treatment with electron beam
- Author
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Young Hee Han, Seong Ok Han, Dong Hwan Cho, and Hyung-Il Kim
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Polypropylene ,Materials science ,Polymers and Plastics ,biology ,General Chemical Engineering ,Organic Chemistry ,Compression molding ,Thermosetting polymer ,Dynamic mechanical analysis ,biology.organism_classification ,Kenaf ,chemistry.chemical_compound ,chemistry ,Materials Chemistry ,Fiber ,Composite material ,Biocomposite ,Natural fiber - Abstract
Environmentally friendly biocomposites were made using plant-based natural fibers, such as henequen and kenaf. The natural fiber reinforced polypropylene (PP) and unsaturated polyester (UP) biocomposites were examined in terms of the reinforcing effect of natural fibers on thermoplastic and thermosetting polymers. Kenaf (KE) and henequen (HQ) fibers were treated with an electron beam (EB) of 10 and 200 kGy doses, respectively, or with a 5 wt% NaOH solution. Four types of biocomposites (KE/PP, HQ/PP, KE/UP and HQ/UP) were fabricated by compression molding and each biocomposite was characterized by dynamic mechanical analysis and thermogravimetric analysis. The kenaf fiber had the larger reinforcing effect on the dynamic mechanical properties of both PP and UP biocomposites than the henequen fiber. The highest storage modulus was obtained from the biocomposite with the combination of UP matrix and 200 kGy EB treated kenaf fibers.
- Published
- 2008
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22. The Effect of Corporate Strategy and IT Role on the Intent for IT Outsourcing Decision
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Dong-Hwan Cho
- Published
- 2008
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23. Evaluation of Bulk-Sensitive Structural Characteristics of Oxidized Single-Walled Carbon Nanotubes using Solution Phase Optical Spectra
- Author
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Dong-Hwan Cho, Satish Kumar, Dae-Suk Bang, and Geon-Woong Lee
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Materials science ,Band gap ,Sonication ,Physics::Medical Physics ,Analytical chemistry ,Energy Engineering and Power Technology ,Carbon nanotube ,Spectral line ,law.invention ,Catalysis ,Inorganic Chemistry ,Metal ,Condensed Matter::Materials Science ,symbols.namesake ,law ,Materials Chemistry ,Condensed Matter::Other ,Renewable Energy, Sustainability and the Environment ,Process Chemistry and Technology ,Organic Chemistry ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Optical properties of carbon nanotubes ,visual_art ,Ceramics and Composites ,symbols ,visual_art.visual_art_medium ,Raman spectroscopy - Abstract
A method for evaluating bulk sensitive structural characteristics of unpurified, as-purified, and acid treated single walled carbon nanotubes (SWNTs) was described in the present study. The optical spectra of SWNT solutions were well resolved after prolonged sonication and they were correlated to the diameter and the distribution of nanotubes. The acid-treated SWNTs were similar to as-purified SWNTs in terms of catalyst residue, radial breathing mode (RBM) in the Raman spectra, and the first band gap energy of semiconducting tubes in the optical spectra. The solution phase optical spectra were more sensitive to changes in the small diameter and metallic tubes after the acid treatment than were the RBM spectra.
- Published
- 2007
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24. Business Models and Business Strategies of UCC Web Sites in Korea
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Dong-Hwan Cho
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Openness to experience ,Profit model ,Business ,Business model ,Marketing ,Sociocultural evolution - Abstract
UCC stands right in the center of web 2.0 era represented by share, participation, and openness. Moving picture UCC has been facilitated by If infrastructure advancement and sociocultural changes. Its prospect is expected to be brighter because presumers are spreading, cost of creating and distributing contents is greatly reduced, and there is going to appear more companies utilizing UCC in improving firm`s competitiveness. In this paper, various UCC business models are analyzed and hot major issues faced by UCC industry such as profit model and copyright are discussed. In addition, strategies for UCC business success and opportunities and challenges confronted by UCC businesses are discussed.
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- 2007
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25. Different Characteristics of the Bright Branches of the Globular Clusters M15 and M92
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Sang-Gak Lee, Dong-Hwan Cho, Kyung Jin Sim, and Young-Beom Jeon
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Physics ,Stars ,Space and Planetary Science ,Globular cluster ,Astronomy and Astrophysics ,Astrophysics ,RR Lyrae variable ,Instability strip - Abstract
We carried out wide-field BVI CCD photometric observations of the GCs M3 and M13 using the BOAO 1.8 m telescope equipped with a 2K CCD. We present CMDs of M3 and M13. We have found AGB bumps at V = 14.85 for M3 at V = 14.25 for M13. It is found that AGB stars in M3 are more concentrated near the bump, while those in M13 are scattered along the AGB sequence. We identified the RGB bump of M3 at V = 15.50 and that of M13 at V = 14.80. We have estimated the ratios R and R2 for M3 and M13 and found that of R for M3 is larger than that for M13 while R2's for M3 and M13 are similar when only normal HB stars are used in R and R2 for M13. However, we found that R's for M3 and M13 are similar while R2 for M3 is larger than that for M13 when all the HB stars are included in R and R2 for M13. We have compared the observed RGB LFs of M3 and M13 with the theoretical RGB LF of Bergbusch & VandenBerg at the same radial distances from the cluster centers as used in R and R2 for M3 and M13. We found "extra stars" belonging to M13 in the comparison of the observed RGB LF of M13 and the theoretical RGB LF of Bergbusch & VandenBerg. In the original definition of R of Buzzoni et al., N(HB) corresponds to the lifetime of HB stars in the RR Lyrae instability strip at log T_eff = 3.85. So, the smaller R value resulting for M13 compared with that for M3 in the case where only normal HB stars are included in R and R2 for M13 may be partially caused by "extra stars", and the similar R's for M3 and M13 in the case where the all HB stars are included in R and R2 for M13 may be caused by "extra stars" in the upper RGB of M13. If "extra stars" in the upper RGB of M13 are caused by an effective "deep mixing" these facts support the contention that an effective "deep mixing" could lead to different HB morphologies between M3 and M13 and subsequent sequences.
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- 2007
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26. Interfacial shear strength and thermal properties of electron beam-treated henequen fibers reinforced unsaturated polyester composites
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Won Ho Park, Seong Ok Han, Dong Hwan Cho, and Yan Song Pang
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Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Nanochemistry ,Compression molding ,Dynamic mechanical analysis ,Thermal expansion ,Materials Chemistry ,Thermomechanical analysis ,Irradiation ,Fiber ,Composite material ,Natural fiber - Abstract
Natural fiber henequen/unsaturated polyester (UPE) composites were fabricated by means of a compression molding technique using chopped henequen fibers treated at various electron beam (EB) dosages. The interfacial shear strength (IFSS), dynamic mechanical properties, and thermal expansion behavior were investigated through a single fiber microbonding test, fractographic observation, dynamic mechanical analysis, and thermomechanical analysis, respectively. The results indicated that the interfacial and dynamic mechanical properties significantly depended on the level of the EB treatment irradiated onto the henequen fiber surfaces. The effect of EB treatment on the IFSS, storage modulus and fracture surface of the henequen/UPE composites agreed with each other. The results of this study also suggested that the modification of henequen fiber surfaces at 10 kGy EB is the most effective for improving the interfacial properties of the henequen/UPE composites.
- Published
- 2005
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27. Effect of applied voltage on the fluorescence behavior of E7/NOA-65 PDLC films
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Dae Suk Bang, Gyeong Mo Yang, Dong Hwan Cho, and Sang Cheol Lee
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,business.industry ,General Chemical Engineering ,Organic Chemistry ,Analytical chemistry ,Polymer ,Polymer engineering ,Threshold voltage ,Hysteresis ,chemistry ,Liquid crystal ,Rise time ,Electric field ,Materials Chemistry ,Optoelectronics ,business ,Voltage - Abstract
The present result indicates that the steady-state fluorescence behavior of E7/NOA-65 polymer disperse liquid crystal films prepared by a photoinitiated-polymerization induced phase separation method plays a significant role in understanding electro-photophysical response and hysteresis on varying applied electric fields. The fluorescence technique is sensitive to molecular alignment of LC molecules in the polymer matrix and it also provides useful quantitative information on the rise time, the threshold voltage and the driving voltage of a PDLC system.
- Published
- 2005
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28. The effect of cure history on the fluorescence behavior of an unsaturated polyester resin with a fluorescence probe
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Suk Hyang Yun, Dae Suk Bang, Il Hyun Park, and Dong Hwan Cho
- Subjects
Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,technology, industry, and agriculture ,Analytical chemistry ,Nanochemistry ,Unsaturated polyester ,Fluorescence ,Isothermal process ,Polymer engineering ,chemistry.chemical_compound ,Monomer ,chemistry ,Propane ,Materials Chemistry ,Curing (chemistry) - Abstract
We have extensively characterized the fluorescence behavior of unsaturated polyester (UP) resin in the absence and presence of a 1,3-bis-(1-pyrenyl)propane (BPP) fluorescent probe at various dynamic and isothermal cure histories by means of a steady-state fluorescence technique using a front-face illumination equipment. In addition, we explored the effect of the fluorescence intensity on the relaxation of the fluorescent probe in the UP resin by resting the dynamically and isothermally cured resin at ambient temperature and pressure for 24 h. The monomer fluorescence intensity, which has two characteristic peaks at 376 and 396 nm, changed noticeably depending on the cure temperature and time and provided important information with respect to the molecular and photophysical responses upon curing. The result of the fluorescence study indicates that the increased local viscosity and restricted molecular mobility of the UP resin surrounding the BPP probe after curing are both responsible for the enhancement of the monomer fluorescence intensity. Our results also demonstrate that once the BPP probe has enough time to rearrange and become isolated prior to fluorescence, a sufficient amount of fluorescence is emitted. Therefore, we note that the fluorescence behavior of this UP resin system is influenced strongly by the relaxation process of the fluorescent probe in the resin as well as process used to cure the resin.
- Published
- 2004
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29. Influence of silane coupling agents on the interlaminar and thermal properties of woven glass fabric/nylon 6 composites
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Kim Jun Kyung, Park Min, Lim Soon Ho, Suk Hyang Yun, Dong Hwan Cho, Geon Lee, and Sang Soo Lee
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Thermogravimetric analysis ,Silanes ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Dynamic mechanical analysis ,Methacrylate ,Silane ,chemistry.chemical_compound ,Nylon 6 ,chemistry ,Diamine ,Materials Chemistry ,Thermal stability ,Composite material - Abstract
In this study, the influence of silane coupling agents, featuring different organo-functional groups on the interlaminar and thermal properties of woven glass fabric-reinforced nylon 6 composites, has been by means of shortbeam shear tests, dynamic mechanical analysis, scanning electron microscopy, and thermogravimetric analysis. The results indicate that the fiber-matrix interfacial characteristics obtained using the different analytical methods agree well with each other. The interlaminar shear strengths (ILSS) of glass fabric/nylon 6 composites sized with various silane coupling agents are significantly improved in comparison with that of the composite sized commercially. ILSS of the composites increases in the order: Z-6076 with chloropropyl groups in the silanes >Z-6030 with methacrylate groups >Z-6020 with diamine groups; this trend is similar to that of results found in an earlier study of interfacial shear strength. The dynamic mechanical properties, the fracture surface observations, and the thermal stability also support the interfacial results. The improvement of the interfacial properties may be ascribed to the different chemical reactivities of the reactive amino end groups of nylon 6 and the organo-functional groups located at the ends of the silane chains, which results from the increased chemical reactivity in order chloropropyl >methacrylate >diamine.
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- 2004
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30. Effect of thermal imidization and curing on fluorescence behavior of a phenylethynyl-terminated poly(amic acid)
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Dong Hwan Cho, Gyeong Mo Yang, and Lawrence T. Drzal
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Thermosetting polymer ,Polymer ,Photochemistry ,Oligomer ,chemistry.chemical_compound ,End-group ,chemistry ,Polymer chemistry ,Materials Chemistry ,Imide ,Thermal analysis ,Curing (chemistry) ,Polyimide - Abstract
The imidization and cure reaction of a thermosetting phenylethynyl-terminated amic acid (LaRC PETI-5) in film form have been monitored as a function of temperature by means of a steady-state fluorescence technique using a front-face illumination method. The variation of the fluorescence emission spectra of LaRC PETI-5 can be divided into four temperature regions; Region I: below 150°C, Region II: 150–250 °C, Region III: 250–350 °C, and Region IV: above 350 °C. The fluorescence spectra in Region I are largely influenced by residual N-methyl-2-pyrrolidinone in the polymer and also slightly by partial imidization of the polymer. There is a combined effect of imidization and solvent removal on the fluorescence behavior in Region II. The spectra in Regions III and IV are due significantly to the cure reaction of LaRC PETI-5 and to a post-cure effect of the polyimide, respectively. This spectroscopic evidence indicating the transformation of the amic acid imide oligomer into the corresponding polyimide via imidization and cure, agrees well with thermal analysis results obtained previously. The intermediate stage of cure in the range of 250–300 °C predominantly influences the change of the fluorescence intensity. The later stage above 300 °C significantly influences the position of the spectrum. This fluorescence study also supports the mechanism proposed in earlier work that the crosslinking reaction takes place at the reaction sites in the conjugated polyene and the phenylethynyl end group in the polyimide chain.
- Published
- 2003
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31. Effects of quasi-carbonization process on the mechanical properties of spun yarn type quasi-carbon fabrics
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Jong Moon Lee, Jong Kyoo Park, and Dong Hwan Cho
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Materials science ,Polymers and Plastics ,Tension (physics) ,Carbonization ,General Chemical Engineering ,Organic Chemistry ,Nanochemistry ,chemistry.chemical_element ,Modulus ,chemistry ,Scientific method ,Ultimate tensile strength ,Materials Chemistry ,Texture (crystalline) ,Composite material ,Carbon - Abstract
In this paper we have extensively studied what and how processing parameters for quasi-carbonization influence the breaking strength and modulus of resulting quasi-carbon fabrics that are prepared from stabilized PAN fabrics with a spun yarn texture. Seven processing parameters have been considered as follows: applied tension, final heat-treatment temperature, heating rate, heating step, holding time, cooling rate, and purging gas purity. The results indicate that optimal uses of applied tension, final heat-treatment temperature, heating rate, and heating step during quasi-carbonization process are primarily important to increase the tensile properties of quasi-carbon fabrics and holding time, cooling rate, and purging gas purity are less importantly contributed.
- Published
- 2002
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32. The Relation between Near-infrared Luminosity of Red Giant Branch Bumps and Metallicity of Galactic Globular Clusters
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Dong-Hwan Cho and Sang-Gak Lee
- Subjects
Physics ,Space and Planetary Science ,Release point ,Globular cluster ,Metallicity ,Magnitude (astronomy) ,Near-infrared spectroscopy ,RGB color model ,Astronomy and Astrophysics ,Astrophysics ,Luminosity - Abstract
Using photometric data from the 2MASS second incremental release point source catalog we constructed Ks vs. (J-Ks) color-magnitude diagrams (CMDs) of Galactic globular clusters (GGCs) for which the JKs photometric data have been made available up to now. On the CMDs of 13 GGCs we identified RGB bump features and derived luminosities of bumps in Ks and in absolute Ks for 11 of them. We reconfirm the relation between abolute Ks magnitude of bump and metallicity [Fe/H]CG97 or [M/H] such that the luminosity of bump becomes brighter as metallicity [Fe/H]CG97 or [M/H] decreases. This result is similar to that obtained by Ferraro et al. (1999) for the relation between abolute V magnitude of bump and [M/H] based on observations of 47 GGCs which were conducted in the optical region (V vs. (B-V) CMDs). Our results show the same trend as those found by Ferraro et al. (2000) for the relations between abolute Ks magnitude of bump and metallicity [Fe/H]CG97 and [M/H] derived from observations of 8 GGCs in the same near-infrared (K vs. (J-K) CMDs). Combining with the data of Ferraro et al. (2000), we derive a robust relation for the metal-dependent luminosities of the bumps.
- Published
- 2002
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33. Impact of e-Business initiatives on firm value
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Seong Chul Lee, Dong Hwan Cho, and Ho Geun Lee
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Marketing ,Factor market ,Finance ,Electronic business ,Computer Networks and Communications ,business.industry ,Enterprise value ,Event study ,Computer Science Applications ,Market value added ,Management of Technology and Innovation ,Economics ,Digital economy ,Market value ,business ,Capital market ,Industrial organization - Abstract
A growing number of firms are competitively entering into e-Business because they see the high potential of e-Business growth as an opportunity. The positive expectation of the e-Business market leads most firms to go into e-Business, but it is not clear what kinds of benefits firms gain through e-Business. In this paper, we examine whether firms’ economic benefits are related to e-Business activities. For this purpose, we employ event study methodology and assess the cumulative abnormal returns for 782 e-Business initiatives by firms listed in Korean capital markets. The well-known Dot Com Effect is verified empirically by this study. The results of this study indicate that e-Business potential is highly valued in the capital market, and e-Business firms are expected to create significant benefits in the future period.
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- 2002
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34. IDENTIFICATION OF LUMINOUS WHITE DWARF CANDIDATES IN THE GLOBULAR CLUSTERS M13 AND M22 USING HST ACS PHOTOMETRIC DATA
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Tae Seog Yoon, Dong-Hwan Cho, Sang-Gak Lee, and Hyun-Il Sung
- Subjects
Physics ,Globular cluster ,Astronomy ,White dwarf ,Identification (biology) ,General Medicine ,Astrophysics - Published
- 2015
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35. The advantage of using 3-week data to predict response to aripiprazole at week 6 in first-episode psychosis
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Jong-Hoon Kim, Jong-Ik Park, Bumseok Jeong, Young-Chul Chung, Yo-Han Lee, Min-Seong Koo, Jong-Il Park, Sang Woo Hahn, Sung-Wan Kim, Seung-Jae Lee, Seung Hwan Lee, Dong-Hwan Cho, and Seung Ho Rho
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,medicine.drug_class ,Aripiprazole ,Atypical antipsychotic ,Schizoaffective disorder ,Kaplan-Meier Estimate ,Quinolones ,Piperazines ,Young Adult ,Predictive Value of Tests ,Internal medicine ,Republic of Korea ,medicine ,Humans ,Pharmacology (medical) ,Schizophreniform disorder ,Psychiatry ,First episode ,Psychiatric Status Rating Scales ,Positive and Negative Syndrome Scale ,Middle Aged ,medicine.disease ,Psychiatry and Mental health ,Treatment Outcome ,Psychotic Disorders ,Schizophrenia ,Clinical Global Impression ,Female ,Psychology ,medicine.drug ,Antipsychotic Agents - Abstract
We investigated the efficacy and safety of aripiprazole in first-episode psychosis and explored the association between early response and later response to this medication. This was a 6-week, open-label, multicenter trial. The study population consisted of 59 patients with a DSM-IV diagnosis of a schizophreniform disorder, schizoaffective disorder, schizophrenia, or psychotic disorder not otherwise specified. The primary outcome measures were the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression-Severity scale. To assess the safety, we measured the drug-related adverse events, weight, and lipid-related variables. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the response status at weeks 2 and 3 to predict the subsequent response at week 6. Among the 59 participants, 38 were able to complete the 6-week trial. Treatment with aripiprazole resulted in significant improvement in the PANSS and Clinical Global Impression scores over time. The response rate (defined as a ≥30% decrease in the PANSS total score from baseline to the last observation) was 69.1%. The most accurate prediction of later response in terms of negative predictive value and specificity was a reduction in the PANSS total score from baseline to week 3 of at least 20%. Aripiprazole had a modest side effect burden and was characterized by a safe profile with respect to weight and metabolic side effects. These results indicate that aripiprazole is effective and safe in the treatment of first-episode psychosis. The response at week 3, rather than week 2, predicted the later response more accurately.
- Published
- 2013
36. The Effects of Market Orientation, Entrepreneurial Orientation and Social Networks on the Social Performance of Non-profit Organizations
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Dong-Hwan Cho and Jin-Hyuk Hong
- Subjects
Data collection ,ComputingMilieux_THECOMPUTINGPROFESSION ,Social network ,Order (exchange) ,business.industry ,Entrepreneurial orientation ,Multilevel model ,Market orientation ,Corporate social responsibility ,Questionnaire ,Business ,Marketing - Abstract
The main objective of this study is to analyze the effects of market orientation, the entrepreneurial orientation and the social network on the social performance of non-profit organizations and sector in Korea. In order to test research hypotheses, field survey was designed, and by distributing questionnaire survey data collection was performed. After collecting data, hierarchical multiple regression analysis was performed. As a result, the market orientation and the social network were shown to significant effect on the social performance, the innovativeness of the entrepreneurial orientation was also meaningful. In contrast, the risk-taking of the entrepreneurial orientation was not shown to have a significant effect on the social performance.
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- 2012
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37. The Effect of Corporate Strategy and IT Role on the Intent for IT Outsourcing Decision
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Dong-Hwan Cho and Jin-Sung Kim
- Subjects
business.industry ,As is ,Business administration ,Credibility ,Information system ,Business impact ,Strategic management ,Business ,Maturity (finance) ,Knowledge process outsourcing ,Industrial organization ,Outsourcing - Abstract
The Intent for IT outsourcing is commonly categorized as IS Improvement, Business Impact, and Commercial Exploitation. The decision factors for these IT outsourcing include corporate strategy types, IT role, and interaction between these two. Firm size and IT maturity are selected as moderating factors to add the credibility to the research of the effect of IT outsourcing decision making. Analyzing collected data revealed that corporate strategy rather than IT role is more significant factor affecting the intent for IT outsourcing decision. Defenders tend to use IT outsourcing more as a means to improve information systems, compared to analyzers and reactors. Prospectors tend to use IT outsourcing more as a commercial exploitation, compared to analyzers and reactors. Unlike previous researches, the hypothesis that IT role determines outsourcing intent was rejected. It was also rejected that the interaction between corporate strategy types and IT role determines outsourcing intent.
- Published
- 2011
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38. An Analysis of U-Healthcare Business Models and Business Strategies: Focused on Life Insurance Industry
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Dong-Hwan Cho and Jin-Hyuk Hong
- Subjects
Electronic business ,New business development ,Line of business ,Life insurance ,Business analysis ,Business ,Business model ,Marketing ,Business risks ,Business relationship management - Abstract
Recently major developed countries such as U.S. and EU selected U-Health as future growth engine industry, and concentrated their capabilities. Major companies all around the world also entered this U-Health business. Most of the researchers in this field confined their research focus mainly on the elementary technologies for infrastructure buildings. This research systematically investigates U-Health business models with various objectives in diverse sub-areas. For this purpose, the value chain of U-Health industry is analyzed, and then various business models were explored all around the world. Finally, the future changes possible to occur in the life insurance industry were analyzed.
- Published
- 2011
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39. A Study on IT Organization Redesign with IT Governance: Focusing on K Public Corporation in Korea
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Dong Hwan Cho and Hyoung Seop Shim
- Subjects
Engineering management ,Corporate governance ,Job analysis ,Task analysis ,Business ,Corporation ,Task (project management) - Abstract
This study investigated the redesign methods and procedures of IT organization with specific focus on K public corporation. Job analysis was carried out so as to redesign IT organization in K public corporation. Task redesign was also performed and IT organization as well as personnel was assessed. (1) In task analysis, core activities were identified and 96 standard tasks were drawn. (2) IT support, IT delivery, IT operation teams were the target for organization redesign. Bukyoung and Jeju teams were also separated. (3) Previous job organization was restructured.
- Published
- 2011
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40. The Effects of Project, Customer and Vendor Properties on the Conflict of IS Outsourcing Development
- Author
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Haeng-Nam Sung and Dong-Hwan Cho
- Subjects
Customer retention ,Customer advocacy ,Empirical research ,Process management ,Vendor ,business.industry ,Conflict management ,Business ,Concreteness ,Knowledge process outsourcing ,Outsourcing - Abstract
This study aims to investigate the major causes of conflict between clients and vendors in the outsourced IS development. A research model is established based on the prior research of IS outsourcing, system development and conflict. An empirical study was executed using 214 survey questionnaires of project teams composed of client and vendor with PASW 18.0. Research results using multiple regressions show that contract concreteness, requirement constancy, accordance of goals and Technology of Knowledge have negative effects on conflict.
- Published
- 2011
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41. Different Characteristics of the Bright Branches of the Globular Clusters M3 and M13
- Author
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Dong-Hwan Cho, Sang-Gak Lee, Young-Beom Jeon, and Kyung Jin Sim
- Subjects
Space and Planetary Science ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics - Abstract
We carried out wide-field BVI CCD photometric observations of the GCs M3 and M13 using the BOAO 1.8 m telescope equipped with a 2K CCD. We present CMDs of M3 and M13. We have found AGB bumps at V = 14.85 for M3 at V = 14.25 for M13. It is found that AGB stars in M3 are more concentrated near the bump, while those in M13 are scattered along the AGB sequence. We identified the RGB bump of M3 at V = 15.50 and that of M13 at V = 14.80. We have estimated the ratios R and R2 for M3 and M13 and found that of R for M3 is larger than that for M13 while R2's for M3 and M13 are similar when only normal HB stars are used in R and R2 for M13. However, we found that R's for M3 and M13 are similar while R2 for M3 is larger than that for M13 when all the HB stars are included in R and R2 for M13. We have compared the observed RGB LFs of M3 and M13 with the theoretical RGB LF of Bergbusch & VandenBerg at the same radial distances from the cluster centers as used in R and R2 for M3 and M13. We found "extra stars" belonging to M13 in the comparison of the observed RGB LF of M13 and the theoretical RGB LF of Bergbusch & VandenBerg. In the original definition of R of Buzzoni et al., N(HB) corresponds to the lifetime of HB stars in the RR Lyrae instability strip at log T_eff = 3.85. So, the smaller R value resulting for M13 compared with that for M3 in the case where only normal HB stars are included in R and R2 for M13 may be partially caused by "extra stars", and the similar R's for M3 and M13 in the case where the all HB stars are included in R and R2 for M13 may be caused by "extra stars" in the upper RGB of M13. If "extra stars" in the upper RGB of M13 are caused by an effective "deep mixing" these facts support the contention that an effective "deep mixing" could lead to different HB morphologies between M3 and M13 and subsequent sequences., 24 pages, 7 figures, to be published in the AJ
- Published
- 2005
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42. Implication of nociceptin in alterations in cerebral blood flow regulation following postnatal exposure to ethanol in rats
- Author
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Jeong Hee Kim, Su Yeon Ko, Won Suk Lee, and Dong Hwan Cho
- Subjects
medicine.medical_specialty ,Ethanol ,business.industry ,Antagonist ,chemistry.chemical_compound ,Nociceptin receptor ,Basal (phylogenetics) ,medicine.anatomical_structure ,Endocrinology ,Blood pressure ,Neurology ,Cerebral blood flow ,chemistry ,Cerebral cortex ,Internal medicine ,medicine ,Autoregulation ,Neurology (clinical) ,Cardiology and Cardiovascular Medicine ,business - Abstract
This study aimed to investigate whether nociceptin is implicated in the alterations in cerebral blood flow regulation following postnatal exposure to ethanol in Sprague-Dawley rats. Animals received ethanol (2.5 g/kg, s.c.) twice a day, 2 hours apart, on postnatal 6, 7 and 8 days. The changes in regional cerebral blood flow (rCBF) in response to the changes in mean arterial blood pressure were determined at 4-, 8-, and 12-weeks of age by laser-Doppler flowmetry. Hypotension was induced by the gradual withdrawal of blood from arterial catheter, and the reversal of blood pressure was produced by the reinfusion of blood. Expression of nociceptin-like immunoreactivity was determined in dura mater and cerebral cortex using immunohistochemistry. Postnatal exposure to ethanol almost abolished the autoregulation of rCBF in all age groups. Pretreatment with nociceptin (0.138 g/kg, i.p.) but not with [Nphe1]nociceptin(1-13)NH2 (1.38 g/kg, i.p.), a selective competitive nociceptin receptor antagonist, 5 minutes prior to ethanol administration preserved the autoregulation of rCBF in all age groups. Postnatal exposure to ethanol markedly increased the expression of nociceptin-like immunoreactivity in dura mater, which was significantly inhibited by pretreatment with 7-nitroindazole monosodium salt (7-NINA, 50 mg/kg, i.p.) as well as aminoguanidine (1 mg/kg, i.p.) 5 minutes prior to ethanol administration in all age groups. Postnatal exposure to ethanol markedly increased the expression of nociceptin-like immunoreactivity in cerebral cortex, which was significantly inhibited by pretreatment with 7-NINA as well as aminoguanidine 5 minutes prior to ethanol administration in all age groups. The values of arterial blood gas analysis were not significantly different from the basal levels in all groups. These results suggest that nociceptin is deeply implicated in the compensatory mechanisms for the nitric oxide-dependent alterations in CBF autoregulation following postnatal exposure to ethanol.
- Published
- 2005
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43. Clinical relationship and the prognostic factor between serum carcinoembryonic antigen (CEA) and tissue CEA in colorectal cancer patients
- Author
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Dong Hwan Choi, Dong Hoon Shin, Byung Soo Park, and Gyung Mo Son
- Subjects
colorectal cancer ,serum cea ,tissue cea ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 ,Surgery ,RD1-811 - Abstract
Purpose: The aim of this study was to investigate the prognostic factor for elevating serum carcinoembryonic antigen (CEA) in patients with colorectal cancer and to identify clinical usefulness of tissue CEA. Methods: Two hundred and eighty-five patients with colorectal cancer were performed serum CEA tests before and after surgery. Also resected tumors were checked expressions pattern of tissue CEA. Clinicopathologic factors were classified according to patient factors, tumor factors and molecular factors. Patient factors included age, sex, underlying liver disease, smoking history and other cancer history. Tumor factors included tumor size, intestinal obstruction, pathologic T status, lymph node metastasis, tumor differentiation, lymphatic invasion, vascular invasion, perineural invasion. Results: Serum CEA level was markedly elevated in the cytoplasmic pattern of tissue CEA compared to membranous pattern of tissue CEA. As cancer stage progressed, serum CEA level was elevated, which was confined to cytoplasmic pattern of tissue CEA. Independent factors for the elevation of serum CEA by multivariate analysis included tumor size ( ≥ 5 cm) (P = 0.042), complete intestinal Obstruction (P = 0.023) and serum CA 19-9 ( ≥ 37 U/mL) (P = 0.027). p53 overexpression ( ≥ 10%) was related to cytoplasmic pattern in tissue CEA (P = 0.005). Conclusion: The tumor size and bowel obstruction are considered the main factors, which cause the leakage of intracellular CEA. And membranous patterns of tissue CEA can be used in Stage I colorectal cancer patients, as an indicator for early prognosis and recurrence. However, more studies of colorectal population are required for further evaluation.
- Published
- 2015
- Full Text
- View/download PDF
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