17 results on '"Jae-Ik Cho"'
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2. Design of a modified charcoal production kiln for thermal therapy and evaluation of the charcoal characteristics from this kiln
- Author
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Hui Su Lee, Woo Seok Jeon, Yun Ki Kim, Byantara Darsan Purusatama, Ah Ran Kim, Jae Ik Cho, Wae Jung Kim, Hyung Chun Kim, and Nam Hun Kim
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Environmental Engineering ,Bioengineering ,Waste Management and Disposal - Abstract
A modified charcoal kiln was developed for both thermal therapy and charcoal production. The design of a modified kiln for thermal therapy focused on safety and cleanliness, plus the production of good quality charcoal. Two entrances in the kiln were designed for convenient charcoal production and thermal therapy. A barrier wall designed for noxious gases was installed between the adjoining charcoal kilns for safe thermal therapy. Additionally, a fine dust collector was installed to remove the fine dust generated during charcoal production. To verify the safety of the kiln, fine dust and harmful gases, such as carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), and radon (Rn), were measured after the charring process. The quality of the charcoal produced in the thermal therapy kiln was also examined. To evaluate charcoal quality, some physical properties and results from a proximate analysis were evaluated using Korean standards. The measurements of harmful substances and fine dust in the modified charcoal kiln met the criterion of the Ministry of Environment Clean Air Conservation Act in Korea. In addition, there were no noticeable differences in the monthly charcoal characteristics prepared from the thermal therapy kiln, and the charcoal characteristics also met the reference values of the Korea Forest Service.
- Published
- 2019
3. Effect of Alloying Elements on the Thermal Conductivity and Casting Characteristics of Aluminum Alloys in High Pressure Die Casting
- Author
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Jae-Ik Cho, Cheol-Woo Kim, Jung-Han Kim, Min-Suk Oh, and Young-Chan Kim
- Subjects
0209 industrial biotechnology ,Materials science ,Metallurgy ,Metals and Alloys ,chemistry.chemical_element ,02 engineering and technology ,Heat sink ,Die casting ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,Thermal conductivity ,0203 mechanical engineering ,chemistry ,Aluminium ,Thermal radiation ,Casting (metalworking) ,Modeling and Simulation ,High pressure - Published
- 2018
4. Effect of Boron on Electrical and Thermal Conductivities of Aluminum
- Author
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Min-Kyung Park, Jae-Ik Cho, Cheol-Woo Kim, and Seong-Hee Lee
- Subjects
03 medical and health sciences ,0302 clinical medicine ,Materials science ,chemistry ,Aluminium ,Thermal ,chemistry.chemical_element ,02 engineering and technology ,Composite material ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Boron ,030226 pharmacology & pharmacy - Published
- 2016
5. An Improved One-Stage Operation of Cranioplasty and Ventriculoperitoneal Shunt in Patient with Hydrocephalus and Large Cranial Defect
- Author
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Sang Pyung Lee, Young Taek Jung, and Jae Ik Cho
- Subjects
Cranial defect ,medicine.medical_specialty ,Clinical Article ,business.industry ,medicine.medical_treatment ,Decompressive craniectomy ,One-stage operation ,medicine.disease ,Cranioplasty ,Ventriculoperitoneal shunt ,Hydrocephalus ,Surgery ,Shunt (medical) ,Shunt operation ,One stage operation ,medicine ,In patient ,business - Abstract
Objective The risk of complications is high for patients with a large cranial defect and hydrocephalus, undergoing cranioplasty and ventriculoperitoneal (VP) shunt operation. The purpose of this study is to examine retrospectively such cases with complications and contrive an operative technique to reduce complications. Methods Nineteen patients underwent cranioplasty and VP shunt operation due to large cranial defects and hydrocephalus. These patients were divided into two groups: Group A with 10 patients who underwent staged-operations, and Group B with 9 patients who underwent one-stage operation. Their complications in each group were retrospectively reviewed. Another five patients underwent a one-stage operation with temporary occlusion of the distal shunt catheter to improve on the technique and were categorized as Group C. Complications in these groups were compared and analyzed. Results The results of the data analysis revealed that complications related to anesthesia (40%) and those related to antibiotic prophylaxis (30%) were high in Group A, while non-infectious delayed complications (45%) and perioperative complications such as intracranial hematoma (33%) were high in Group B. However, for patients in Group C, it showed less complication with the operative technique devised by these authors, as opposed to two previous procedures. Conclusion In patients with hydrocephalus and a large cranial defect, complications arising from existing one-stage operation or staged-operations can be reduced by implementing the technique of "one-stage operation with temporary occlusion of the distal shunt catheter."
- Published
- 2015
6. Use of the Sundt Clip Graft in a Previously Coiled Internal Carotid Artery Blister-Like Aneurysm
- Author
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Jae Hoon Cho and Jae Ik Cho
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,Case Report ,High morbidity ,Aneurysm ,Multiple paraclinoid aneurysms and Sundt clip graft ,medicine.artery ,medicine ,cardiovascular diseases ,ICA dorsal wall aneurysm ,Surgical approach ,Endovascular intervention ,business.industry ,General Neuroscience ,Clipping (medicine) ,medicine.disease ,Surgery ,surgical procedures, operative ,Endovascular interventions ,cardiovascular system ,Neurology (clinical) ,Neurosurgery ,Blister like aneurysm ,Blood blister-like aneurysm ,Internal carotid artery ,business - Abstract
Owing to the focal wall defect covered with thin fibrous tissues, an aneurysm arising from the dorsal wall of the internal carotid artery (ICA) is difficult to manage either surgically or endovascularly and is often associated with high morbidity and mortality. Unfortunately, the definitive treatment modality of such highly risky aneurysm has not yet been demonstrated. Upon encountering the complex intracranial pathophysiology of such a highly precarious aneurysm, a neurosurgeon would be faced with a challenge to decide on an optimal approach. This is a case of multiple paraclinoid aneurysms including the ICA dorsal wall aneurysm, presented with spontaneous subarachnoid hemorrhage. With respect to treatment, direct clipping with a Sundt graft clip was performed after multiple endovascular interventions had failed. This surgical approach can be a treatment modality for a blood blister-like aneurysm after failed endovascular intervention(s).
- Published
- 2014
7. A Fatal Adverse Effect of Barbiturate Coma Therapy: Dyskalemia
- Author
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Jin Wook Baek, Sang Pyung Lee, Jae Ik Cho, and Hyun Mook Kwon
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Barbiturate ,Hyperkalemia ,medicine.drug_class ,Traumatic brain injury ,medicine.medical_treatment ,Case Report ,Hypokalemia ,Brain injuries ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Adverse effect ,Intracranial pressure ,Coma ,business.industry ,Immunosuppression ,medicine.disease ,030220 oncology & carcinogenesis ,Anesthesia ,Surgery ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
The management guideline for traumatic brain injury (TBI) recommends high-dose barbiturate therapy to control increased intracranial pressure refractory to other therapeutic options. High-dose barbiturate therapy, however, may cause many severe side effects; the commonly recognized ones include hypotension, immunosuppression, hepatic dysfunction, renal dysfunction, and prolonged decrease of cortical activity. Meanwhile, dyskalemia remains relatively uncommon. In this study, we report the case of a hypokalemic patient with severe rebound hyperkalemia, which occurred as a result of barbiturate coma therapy administered for TBI treatment.
- Published
- 2016
8. A Study on Cloud Computing for Detecting Cyber Attacks
- Author
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Seok-Jun Lee, Dong-Ho Won, Jun-Won Lee, and Jae-Ik Cho
- Subjects
World Wide Web ,Computer science ,business.industry ,Cloud computing ,Computer security ,computer.software_genre ,business ,computer - Published
- 2013
9. Power dissipation and area comparison of 512-bit and 1024-bit key AES
- Author
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Setiawan Soekamtoputra, Ken Choi, Jongsub Moon, and Jae-Ik Cho
- Subjects
business.industry ,Computer science ,Encryption software ,Advanced Encryption Standard ,AES implementations ,Encryption ,Computational Mathematics ,Computational Theory and Mathematics ,Modeling and Simulation ,Embedded system ,40-bit encryption ,56-bit encryption ,Advanced Encryption Standard process ,Hardware_ARITHMETICANDLOGICSTRUCTURES ,business ,Key size - Abstract
Advanced Encryption Standard (AES) has replaced its predecessor, Double Encryption Standard (DES), as the most widely used encryption algorithm in many security applications. Up to today, AES standard has key size variants of 128, 192, and 256-bit, where longer bit keys provide more secure ciphered text output. In the hardware perspective, bigger key size also means bigger area and power consumption due to more operations that need to be done. Some companies that employ ultra-high security in their systems may look for a key size bigger than 256-bit AES. In this paper, 128 and 256-bit AES hardware, as well as two variants of an AES encryption algorithm for 512-bit and 1024-bit key size, are implemented and compared in terms of power consumption and area. The experiment is done in 45 nm CMOS technology at 1.1 V using a Synopys DC Compiler and Modelsim and total power consumption and area results are presented and graphically compared.
- Published
- 2013
10. Effects of Mg and Si on Microstructure and Mechanical Properties of Al-Mg Die Casting Alloy
- Author
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Jae-Ik Cho and Cheol-Woo Kim
- Subjects
Mechanical property ,Materials science ,Precipitation (chemistry) ,Phase (matter) ,Alloy ,Metallurgy ,engineering ,Izod impact strength test ,engineering.material ,Elongation ,Microstructure ,Die casting - Abstract
The effects of Mg and Si contents on the microstructure and mechanical properties in Al-Mg alloy (ALDC6) were investigated.The results showed that phase fraction and size of Mg 2 Si and Al 15 (Fe,Mn) 3 Si 2 phase in the microstructure of Al-Mg alloy wereincreased as the Mg and Si contents were raised from 2.5 to 3.5wt%. With Si content of 1.5wt%, freezing range of the alloy wassignificantly reduced and solidification became more complex during the final stage of solidification. While there was no significantinfluence of Mg contents on mechanical properties, Si contents up to 1.5wt%, strongly affected the mechanical properties. Espe-cially elongation was reduced by about a half with more than 1.0wt%Si in the alloy. The bending and impact strength weredecreased with increased amount of Si in the alloy, as well. The lowered mechanical properties are because of the growth of particleshaped coarse Mg 2 Si phase and precipitation of the needle like β -AlFeSi in the microstructure at the last region to solidify due topresence of excess amount of Si in the alloy.Key words : Al-Mg alloy, Die casting, Mechanical property, Microstructure, Thermodynamic simulation, Alloying element effect.
- Published
- 2012
11. A Study on the Malicious Web Page Detection Systems using Real-Time Behavior Analysis
- Author
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Tae-Shik Son, Jongsub Moon, Ick-Sun Kong, and Jae-Ik Cho
- Subjects
World Wide Web ,ComputingMilieux_MANAGEMENTOFCOMPUTINGANDINFORMATIONSYSTEMS ,Software_OPERATINGSYSTEMS ,Computer science ,Web page ,Computer security ,computer.software_genre ,Real time analysis ,computer - Abstract
The recent trends in malwares show the most widely used for the distribution of malwares that the targeted computer is infected while the user is accessing to the website, without being aware of the fact that, in which the harmful codes are concealed. In this thesis, we propose a new malicious web page detection system based on a real time analysis of normal/abnormal behaviors in client-side. By means of this new approach, it is not only the limitation of conventional methods can be overcome, but also the risk of infection from malwares is mitigated.
- Published
- 2012
12. Difference in Solidification Process between Al-Mg Alloy and Al-Si Alloy in Die-Casting
- Author
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Jae-Ik Cho, Se-Weon Choi, Chang-Seog Kang, Young-Chan Kim, and Sung-Kil Hong
- Subjects
Materials science ,business.product_category ,Alloy ,Metallurgy ,engineering.material ,Casting ,Die casting ,Residual stress ,Soldering ,engineering ,6063 aluminium alloy ,Die (manufacturing) ,General Materials Science ,business ,Shrinkage - Abstract
The effect of the alloy systems Al-Mg alloy and Al-Si alloy in this study on the characteristics of die-casting were investigated using solidification simulation software (MAGMAsoft). Generally, it is well known that the casting characteristics of Al-Mg based alloys, such as the fluidity, feedability and die soldering behaviors, are inferior to those of Al-Si based alloys. However, the simulation results of this study showed that the filling pattern behaviors of both the Al-Mg and Al-Si alloys were found to be very similar, whereas the Al-Mg alloy had higher residual stress and greater distortion as generated due to solidification with a larger amount of volumetric shrinkage compared to the Al-Si alloy. The Al-Mg alloy exhibited very high relative numbers of stress-concentrated regions, especially near the rib areas. Owing to the residual stress and distortion, defects were evident in the Al-Mg alloy in the areas predicted by the simulation. However, there were no visible defects observed in the Al-Si alloy. This suggests that an adequate die temperature and casting process optimization are necessary to control and minimize defects when die casting the Al-Mg alloy. A Tatur test was conducted to observe the shrinkage characteristics of the aluminum alloys. The result showed that hot tearing or hot cracking occurred during the solidification of the Al-Mg alloy due to the large amount of shrinkage.
- Published
- 2012
13. Dynamic learning model update of hybrid-classifiers for intrusion detection
- Author
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Jae-Ik Cho, Jongsub Moon, Taeshik Shon, and Ken Choi
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business.industry ,Computer science ,Network security ,Intrusion detection system ,Machine learning ,computer.software_genre ,Signature (logic) ,Theoretical Computer Science ,Data set ,Hardware and Architecture ,Dynamic learning ,Pattern recognition (psychology) ,Artificial intelligence ,Data mining ,business ,computer ,Software ,Information Systems - Abstract
Machine Learning as network attack detection is one of the popular methods researched. Signature based network attack detection is no longer convinced the efficiency in the diversified intrusions (Limmer and Dressler in 17th ACM Conference on Computer and Communication Security, 2010). Moreover, as the various Zero-day attacks, non notified attacks cannot be detected (Wu and Banzhaf in Appl Soft Comput 10(1):1---35, 2010). This paper suggests an effective update method of data set on Machine Learning to detect non notified attacks. In addition, this paper compares and verifies the effects of Machine Learning Detection with updated data set to the former methods.
- Published
- 2011
14. Phase stability determination of the Mg–B binary system using the CALPHAD method and ab initio calculations
- Author
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Sungtae Kim, Chang-Seog Kang, Jung-Chan Bae, Donald S. Stone, Jae-Ik Cho, and Chang-Yeol Jeong
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Superconductivity ,Chemistry ,Magnesium ,Phase stability ,Mechanical Engineering ,Metals and Alloys ,chemistry.chemical_element ,Decomposition ,Condensed Matter::Materials Science ,Mechanics of Materials ,Ab initio quantum chemistry methods ,Condensed Matter::Superconductivity ,Materials Chemistry ,Physical chemistry ,Binary system ,CALPHAD ,Phase diagram - Abstract
Knowledge of the Mg–B binary phase diagram is important in for the synthesis of superconducting MgB2 and of potential, new Mg–B alloys. However, the literature phase diagram is highly uncertain because it was originally constructed by guessing the decomposition temperatures of magnesium boride phases. We therefore utilized the CALPHAD method and ab initio calculations to compute thermodynamic model parameters to determine the decomposition temperatures of magnesium borides and re-assess the Mg–B binary phase diagram.
- Published
- 2009
15. A Study on Static Analysis Model of Mobile Application for Privacy Protection
- Author
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Seil Kim, Dong Hoon Lee, Hee Won Myeong, and Jae Ik Cho
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Parsing ,Computer science ,Privacy software ,Compromise ,media_common.quotation_subject ,Smart device ,Static analysis ,computer.software_genre ,Computer security ,law.invention ,law ,Android (operating system) ,computer ,Private information retrieval ,Personally identifiable information ,media_common - Abstract
Since mobile application market drastically extended, there have been many problems related to proliferative malicious applications that leak user’s private information stored in own smart device. In Korea, government strives to protect smart device users from these problems and to establish legal basis through ‘Privacy Act’ as a preceding step but studies on analysis models and verification tools for mobile application have not yet much developed. The purpose of this research is to suggest an analysis system to prevent propagation of harmful applications, which compromise the user’s personal information, by extracting signatures from malicious code samples detected in Android. Maliciousness of the applications has determined by learning their parsing information on the components such as DEX, Manifest, SO etc.
- Published
- 2011
16. Comparative Analysis of Cervical Lateral Mass Screw Insertion among Three Techniques in the Korean Population by Quantitative Measurements with Reformatted 2D CT Scan Images: Clinical Research
- Author
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Jae-Ik Cho and Dae-Hyun Kim
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medicine.medical_specialty ,Clinical Article ,medicine.diagnostic_test ,business.industry ,Korean population ,General Neuroscience ,Vertebral artery ,Lateral mass ,Computed tomography ,Surgery ,Transversal plane ,medicine.anatomical_structure ,medicine.artery ,medicine ,Neurology (clinical) ,Cadaveric spasm ,business ,Nuclear medicine ,Cervical vertebrae ,Fixation (histology) - Abstract
Objective Our purpose of this study is to compare insertion angles and screw lengths from Roy-Camille, Magerl, and our designed method for cervical lateral mass screw fixation in the Korean population by quantitative measurement of reformatted two dimensional (2D) computed tomography (CT) images. Methods We selected thirty Korean patients who were evaluated with thin section CT scans and reconstruction program to obtain reformatted 2D-CT images of the transversal plane passing the cranio-caudal angle using three different techniques. We measured the minimum angle to avoid vertebral artery (VA) injury, the ideal angle and depth for bicortical screwing of cervical lateral mass. Morphometric measurements of the lateral masses from C3-C7 were also taken. Results In all three techniques, the mean safety angles from the VA were less than 8 degrees and the necessary depth of the screw was about 14 mm for safety to the VA and for the bicortical purchase. In our designed technique, the mean beta angles of each level from C3 to C7 were 29.0, 29.8, 29.5, 26.3, and 23.9 degrees, respectively. Conclusion Results of this study and data from the literature indicate that differences may exist between the Korean and Western people in the length and angle for ideal lateral mass screw fixation. In addition, our technique needs further cadaveric and clinical study for safety and efficacy for being performed as alternative method for cervical lateral mass fixation.
- Published
- 2008
17. Cranioplasty Using a Modified Split Calvarial Graft Technique in Cleidocranial Dysplasia
- Author
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Young Taek Jung, Jae Ik Cho, and Sang Pyung Lee
- Subjects
medicine.medical_specialty ,Dentition ,Cleidocranial Dysplasia ,business.industry ,General Neuroscience ,medicine.medical_treatment ,Case Report ,Congenital calvarial defect ,medicine.disease ,Cranioplasty ,Cleidocranial dysplasia ,Split calvarial graft ,Surgery ,Midface hypoplasia ,Skull ,medicine.anatomical_structure ,Dysplasia ,medicine ,Aplastic clavicles ,Forehead ,Neurology (clinical) ,business - Abstract
Cleidocranial dysplasia is a well-documented rare autosomal dominant skeletal dysplasia characterized by hypoplastic/aplastic clavicles, brachycephalic skull, patent sutures and fontanelles, midface hypoplasia, and abnormalities of dentition. Patients with cleidocranial dysplasia often complain about undesirable esthetic appearance of their forehead and skull. Notwithstanding many studies of molecular, genetics and skeletal abnormalities of this congenial disorder, there have been very few written reports of cranioplasty involving cleidocranial dysplasia. Thus, we report a rare case of successful cranioplasty using a modified split calvarial graft technique in patient with cleidocranial dysplasia.
- Published
- 2015
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