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A steel slit damper has been used to enhance the seismic performance of structures with several advantages. The damper can be easily manufactured at a low cost. Furthermore, it can dissipate a significant amount of seismic energy through the stable hysteretic behavior of steel. This study presents a preliminary investigation of the development of a composite steel slit damper that can respond effectively at multiple levels of seismic loading. The performance of the prototype composite steel slit damper is investigated in both experimental and analytical ways. In the experiments, the specimen shows the stable hysteretic response with sufficient ductility, where the multi-phased response is observed in the incremental-amplitude cyclic loading case. Furthermore, a nonlinear numerical analysis that combines both kinematic hardening and isotropic hardening models can reliably describe such characteristics.

Recently, nonvolatile systems with nonvolatile flip-flops (NVFFs) have gained prominence for their energy efficiency in energy-harvesting devices and battery-operated Internet of Things applications. They are normally-off instantly-on, and thus, can save energy effectively owing to their zero standby power consumption. An NVFF stores the computing state in nonvolatile memories (NVMs) when the power is off. A ferroelectric field-effect transistor (FeFET) is one of the most promising NVMs owing to its high $\text{I}_{\mathrm {on}}/\text{I}_{\mathrm {off}}$ ratio and low write power. Three FeFET-based NVFFs (previous FeFET-out NVFF-1/-2 and FeFET-in NVFF) were recently proposed to improve the area, power, and speed; however, they still have their own problems. Previous FeFET-out NVFF-1 has large area overhead and previous FeFET-out NVFF-2 does not properly perform restore operation. Previous FeFET-in NVFF has a long clock-to-Q delay and high operating energy. This paper introduces two novel FeFET-based NVFFs (proposed FeFET-out and -in NVFFs). Proposed FeFET-out NVFF reduces the large area overhead of previous FeFET-out NVFF-1 and corrects the malfunction in the restore operation of previous FeFET-out NVFF-2. Proposed FeFET-in NVFF achieves a better clock-to-Q delay, operating energy, and area than the previous FeFET-in NVFF. Monte Carlo simulations based on an industry-compatible 10-nm FinFET model are performed for a comparative analysis. Proposed FeFET-out NVFF achieves 17.6% smaller area with slightly higher (6.3%) operating energy and only 0.8% slower clock-to-Q delay than previous FeFET-out NVFF-1. Proposed FeFET-in NVFF achieves 18.9% shorter clock-to-Q and 3.0% smaller operating energy with 8.7% smaller area than the previous FeFET-in NVFF.

Background and Objectives Several studies have assessed the impact of laryngopharyngeal reflux disease (LPRD) on the health-related quality of life (HR-QoL), showing significant impairment of HR-QoL. This study aims to assess the impact of proton pump inhibitor (PPI) treatment of LPRDs to enhance HR-QoL.Subjects and Method We prospectively collected data from LPRD patients from April 2017 to July 2019. Patients who have reflux symptom index (RSI) of ≥13 or reflux finding score (RFS) of ≥7 were enrolled in this study. We assessed HR-QoL using a questionnaire with EORTC QLQ-H&N35, -C30 on the first visit. Patients were treated with PPI (Ilaprazole 20 mg/day) on their visits at 4, 8, and 12 weeks. RSI and RFS were measured at each visit and HR-QoL was reevaluated on the last visit.Results Ninety-five patients completed the 3-months follow-up and were enrolled in this study. Female : male ratio was 71:24 and the mean age was 57.0±11.9 (27-80). The initial RSI and RFS were 16.3±8.8 and 12.6±2.9, respectively, but were changed to 11.1±9.7 and 9.7±2.6 (p

In this study, experimental variables pertaining to the formation of nano-pillar arrays using p-type silicon were optimized by controlling current density and chamber temperature. Three factors aff...

In this study, we have studied coating method using high reflective White silicon on the whole Zener diode in order to resolve the reducing the luminance of the LED problem caused by the Ze...

The block shear equations specified in the current AISC specification for structural steel buildings and North American cold-formed steel design specifications are based on research results of carbon steel bolted connections. These equations were found to be inapplicable for the welded connections in the literature. This issue is primarily associated with the use of the incorrect assumption on block shear failure mechanism. The present paper examines the accuracy of various block shear equations available in the design specifications and in the literature. The paper also examines the shear hardening capacity and the level of tensile stress over the critical net area with the results of finite element analysis, in which the fracture simulation is considered. It shows that the block shear capacities of lean duplex stainless steel welded connections can be predicted accurately using tensile stress equal to 1.25Fu, as proposed in the literature.

This study investigated patterns of probable posttraumatic stress disorder (PTSD) and their predictors among 2,431 Asian American and 31,455 non-Hispanic White World Trade Center (WTC) Registry participants 2-3 years and 5-6 years after the WTC attack. Participants were divided into four PTSD pattern groups: resilient, remitted, delayed onset, and chronic. Asians had a lower proportion in the resilient group (76.5% vs. 79.8%), a higher proportion in the chronic (8.6% vs. 7.4%) and remitted (5.9% vs. 3.4%) groups, and a similar proportion in the delayed onset group (about 9%) compared to Whites. In multinomial logistic regression analyses, disaster exposure, immigrant status, lower income, pre-attack depression/anxiety, and lower respiratory symptoms were associated with increased odds of chronic and delayed onset PTSD (vs. resilience) among both races. Education and employment were protective against chronic and delayed onset PTSD among Whites only. These results can inform targeted outreach efforts to enhance prevention and treatment for Asians affected by future events.

Carton clamp truck is widely perceived as the high-efficient handling equipment of factory premises and warehouse by its capability of palletless handling. Therefore, the significance of a lab- based handling simulation is becoming higher with the growth of clamp truck usage. In this study, preliminary FEA and design of handling test courses for the lab-based simulation of carton clamp truck handling were performed, and the PSD analyses were performed for the modified one for the test course proposed by Park et al. (2017) as well as ASTM D 6055 and ISTA 3B standards. For the vibration in all directions, the vibration energy intensity analyzed by ISTA 3B standard showed higher than that by the other two cases. A FEA was performed for the handling operation of the sudden stop of the clamps after lifting the target HCP (heavyweight refrigerator corrugated package, w=180 kgf) up to the specified height. The slip distance between the clamp arm and the target HCP was 0.85 mm. The simulation result of 0.85 mm was 3.7 times lower than the experimental result (3.2 mm) obtained by Park et al. (2017), and it was estimated that the deviation comes from both the experimental error by weight imbalance of target HCP, and excessive simplification during the FE modelling of target HCP.

A series of earthquake events give impetus to research on the ductile fracture behavior of steel materials. In the last decades, many fracture models have been developed and utilized in the mechanical or aerospace engineering. Nevertheless, very little application to structural members used in the construction industry has been made due to the lack of a suitable model for the fracture behavior of constructional steel. This paper presents the experimental and finite element (FE) technique to predict ductile fracture in mild carbon structural steel (SS275) sheets, which has been widely used in building structures. The post-necking true stress–strain responses were successfully estimated using the weighted-average method. The Bao and Wierzbicki (BW) model, which requires only two model parameters, was selected for the identification of fracture locus. Each model parameter was calibrated from uniaxial tension and in-plane shear specimens with the aid of digital image correlation (DIC) and finite element analysis. Fracture simulation was then performed and validated based on the experimental results of the specimens under combined tension and shear stress state.

Conventional channel estimation schemes may require for the transmission of orthogonal pilot signal for each antenna in frequency-division duplex (FDD) transmission systems. It is of great concern to get channel information with an affordable signaling overhead in FDD massive multi-input multi-output (m-MIMO) transmission environments. The signaling overhead for the channel estimation can be reduced by exploiting the channel correlation matrix (CCM) of m-MIMO channel. When the m-MIMO channel is correlated in spatial domain, the channel information can be estimated with reduced pilot signaling overhead. However, the estimation performance may seriously be affected by the accuracy of CCM. In this paper, we investigate the effect of CCM accuracy on the m-MIMO channel estimation and verify it by computer simulation.

Objective Bitter taste receptors (TAS2Rs) are expressed in the extraoral tissues, where they possess various physiological functions. This study is to characterize TAS2Rs expression in normal and allergic nasal mucosa and analyse nasal symptom after challenge with bitter tastes to evaluate their pathophysiological function in normal and allergic nasal mucosa. Methods The expression levels of TAS2Rs (TAS2R4, 5, 7, 10, 14, 39, and 43) in nasal mucosa were investigated by real-time PCR, Western blot, and immunohistochemistry. The expression levels of TAS2Rs and Ca(2+) imaging in cultured epithelial cells were measured after stimulation with type 2 cytokines (IL-4, IL-5, and IL-13) or bitter tastes. Nasal symptoms in control subjects and allergic rhinitis patients using visual analogue score and acoustic rhinometry were evaluated before and after stimulation with bitter tastes. Vascular diameter of rat nasal septum was measured before and after treatment with bitter tastes. Results TAS2Rs tested here were expressed in nasal mucosa where they were commonly distributed in superficial epithelium, submucosal glands, and endothelium. Their expression levels are increased in allergic nasal mucosa and up-regulated in cultured epithelial cells simulated with type 2 cytokines. After treatment with bitter tastes, intracellular Ca(2+) signalling was increased in cultured epithelial cells, and vascular constriction was found in rat nasal septum. Increased nasal patency was observed in human nasal mucosa without pain or sneezing. Conclusion and clinical relevance TAS2Rs are constitutively expressed in human nasal mucosa and their expression levels are increased in allergic nasal mucosa, where they could potentially contribute to shrinkage of normal and allergic nasal mucosa.

The purpose of this study is to analyze the relations of innovation and productivity following the introduction of ICT and the effects in the process of innovative investments activity-innovation-productivity, not only by finding causes and effects. For this purpose we conducted surveys of SMEs classified into 7 categories by type of business. To put it concretely, this study was performed to find out the foactors which allow companies to secure competitiveness by enhancing of innovative measures through ICT, and to further analyze the political implications for the development of small and medium-size business by conducting an empirical analysis of the process, from the determination of innovative investments all the way through to production. Analysis model used CDM model using econometric methods such as multiple regression analysis and multinominal logit analysis to produce results. Also we established and analyzed models of innovation investment determinants, innovation determinants and productivity determinants to analyze specifically the relations between ICT and productivity.

Internal short circuit of a lithium polymer battery (4.6 Ah capacity and 4.30 V charging voltage) with a ceramic-coated separator has been investigated by infrared measurement during nail penetration. The surface temperatures at nail penetration area and battery body were simultaneously measured by infrared camera and, as a result, three different failure modes have been proposed. The battery with 100% of SOC experiences thermal runaway phenomenon by means of the second internal short circuit. The batteries with low SOC (0% and 50% of SOC) were also investigated to identify the phenomena occurred in SOC 100% battery (the second internal short circuit), but neither fire nor explosion in the battery with low SOC was observed. The analysis of burr status after nail penetration demonstrates that it is quite important factor related to the failure modes. The results of this study can be applied to the design of safe battery.

Summary Objectives Maximal extrathyroidal extension (ETE) is known to be an important prognostic factor in papillary thyroid carcinoma (PTC). However, the significance of minimal ETE is controversial. The aim of this study was to investigate the clinicopathologic characteristics and prognostic significance of minimal vs maximal ETE in PTC. Materials and methods A group of 967 patients who underwent thyroidectomy for PTC in a tertiary hospital between January 2000 and December 2011 were studied retrospectively. Patients were classified into three groups: absence of ETE, and minimal and maximal ETE. The minimal ETE group was further categorized into two subgroups according to invasion of strap muscles or no invasion (STI+ and STI−). Results Gender did not differ between the three groups of patients. The mean age of the patients with maximal ETE was significantly higher than in those belonging to the other groups. Tumor size, bilaterality, lymph node metastasis and stage increased significantly according to the degree of ETE. Recurrence and survival rates did not differ between the absence and minimal ETE groups, or between the STI− and STI+ subgroups of minimal ETE. However, the maximal ETE group had significantly higher recurrence and lower survival rates than the other groups (P Conclusion Maximal ETE is a significant factor for poor prognosis. However, minimal ETE is not associated with increased recurrence or decreased survival in patients with PTC.

As the development of structural system and material enable to construct many high-rise buildings. However, high rise buildings are vulnerable to the strong wind rather than seismic excitation, because they have relatively long period. Recently, intensity and frequency of extreme wind such as hurricane and typhoon have been increased with the weather change all over the world. Therefore, in this study, 50-story building with three types of braces which are diagonal brace, X-brace, Chevron brace are modelled and compared with non-braced 50-story building by changing wind speed. Finally, all the results from four cases are compared for wind performances. As a result, buildings reinforced with X-brace and Chevron braces have a good performance subjected to the strong wind.

As extension of the previous two-surface model in plasticity, a two-surface model for viscoplasticity is presented herein. In order to validate and investigate the performance of the proposed model, several numerical simulations are undertaken especially for structural steel under monotonic and cyclic loading cases, where experimental results and numerical results from the rate dependent kinematic hardening model are also provided for the reference. For all the cases studied, the proposed model can appropriately account for the rate-effects in both maximum stress and hysteretic shapes.

A radiographic analysis with scoliosis patients.To analyze correlations between sagittal spinal alignment and coronal scoliotic curvature.Sagittal spinal alignment and scoliosis may have a significant relationship, and schematic analysis is needed.The study group was comprised of 163 patients with adolescent idiopathic scoliosis. Subjects underwent anteroposterior and lateral radiographs of the whole spine including hip joints. The radiographic parameters used were magnitude, location and direction of curve, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sagittal balance, sacral slope, and pelvic angle. Subjects were classified into 4 groups according to the severity of coronal curvature: Cobb angle ≤20 degrees, Cobb angle 21-40 degrees, Cobb angle 41-60 degrees, and Cobb angle60 degrees. In addition, subjects were divided into 4 subgroups according to Roussouly's classification (types 1-4) of sagittal spinal shape. Schematic analysis was performed to determine the relationship between coronal and sagittal parameters.Analysis of parameters with severity of coronal curvature, thoracic kyphosis, and sacral slope were significantly higher in high-grade scoliosis (P0.05). However, the pelvic angle was higher in low-grade scoliosis, and sagittal balance showed a significantly higher positive value in low-grade scoliosis (P0.05). In the analysis of sagittal spinal shapes, Roussouly groups 3 and 4 showed more severe scoliosis with higher lumbar lordosis and thoracic kyphosis (P0.05). In addition, Roussouly group 1 demonstrated a significantly higher incidence of low-grade scoliosis, whereas groups 3 and 4 had a higher incidence of high-degree scoliosis by cross-relation analysis (P0.05).A significant relationship exists between sagittal spinal shape and coronal curvature in scoliosis. Understanding the biplanar shapes of scoliosis may be helpful to the surgeons.

Conventional channel estimation schemes may require for the use of orthogonal pilot signals for each antenna in frequency-division duplex (FDD) wireless systems. It is a very challenging issue to get channel information with an affordable signaling overhead in massive multi-input multi-output (m-MIMO) FDD transmission environments. The signaling overhead for the channel estimation can be reduced by exploiting the downlink channel correlation matrix (DCCM) of m-MIMO channel. With the use of DCCM, the channel information can be estimated using a reduced number of pilot signals. However, the accuracy of DCCM may seriously affect the estimation performance. In this paper, we consider the estimation of DCCM in m-MIMO transmission environments. Since the distance between a base station and a user is much larger than that between antennas, a set of antenna pairs of equal distance may experience similar spatial correlation due to the far-field effect. We consider the estimation of DCCM by averaging the correlation of these antenna pairs without reception of a large number of pilot signals, significantly reducing the pilot signaling overhead. We also consider the improvement of estimated DCCM by dropping out inaccurate correlation terms. Finally, we verify the proposed scheme by computer simulation.

Heavy duty coating is playing an important role in the field of heavy industry in the development of the shipbuilding and plant industries. Heavy duty coating has the very important function of protecting steel under serious corrosive conditions. The airless tip used for heavy duty coating is an essential part that determines the spray pattern of the paint. This research investigated the injection properties of three airless tips(numbers 521, 523, and 525) by using particle image velocimetry(PIV). The velocity and turbulent intensity according to pressure change with each tip type were investigated by using PIV. If the pressure is greater, the turbulent intensity becomes stronger and the break up of particles becomes bigger as the tip number gets smaller. The velocity is the fastest in the center and decreases in the radial direction.

In this paper, methods to institute a sustainable safety inspection system for e xtent multiple dwellings in Korea are presented. The results of the study are summarized below. First, on the basis of a study on the safety inspection systems for multiple dwe llings in Japan and the United States, the state of the safety inspection systems and the policies for multiple dwellings in Korea is exa mined. Subsequently, the weaknesses of the Korean safety inspection systems and the need to revise them are discussed. Second, the housing circumstances in Korea, Japan, and the United States are analyzed and compared, including laws on safety inspection for multiple dwellings, targets and items of inspection, qualifications for inspection, building history systems, and qualified professionals for safety inspection. On the basis of the analysis and com parison, the differences between the systems of the three nations and the issues that need to be introduced in Korea are presented. Third, based on the safety inspection experiences in Japan and the United States, new directions of safety inspection and methods to enhance current systems for multiple dwellings in Korea are proposed.

In this study, numerical simulations and performance evaluation has been carried out to investigate performance characteristics of air-type high pressure piston pump. ANSYS and CFX were applied for analyzing the structure and flow behavior of air-type high pressure piston pump, respectively. The performance evaluation of high pressure piston pump was performed experimentally, the results were compared with simulation. It was found that the freezing phenomenon was improved by 20% and the pressure fluctuation decreased by 50%, compared with the previous pump.

Four countries are participating in exposure assessment for Mobi-Kids Study. Each country evaluates RF and ELF exposure from mobile phones considering telecommunication system and environment in the corresponding area. The results will be used to determine accumulation exposure level of each subject in case and control groups to assess the potential carcinogenic effects of childhood and adolescent exposure to radio frequency(RF) and extremely low frequency( ELF) from mobile phones on the central nervous system. This paper analyzes exposure types of mobile phones which have been used in Korea for about 10 years, based on Mobi-Kids protocol. It includes investigation of mobile phone models released in the domestic market, design of numerical phone models to represent each exposure type, and measurement of ELF radiation from mobile phones.

The objective of this study is to apply a constitutive damage model for cyclic response of E-shaped dampers as well as metal and metallic plate dampers in order to be used in more broad areas such as material and component levels. The seismic isolation system used as sliding bearings and metallic dampers undergoes almost elastoplastic behavior due to seismic excitation. Accordingly, a two surface damage model is applied to understand inelastic behavior and to evaluate the potential damaged state of E-shaped dampers in the seismic isolation system. This damage model is originally formulated through a thermodynamic approach based on the entropy production equation. The cyclic damage model proposed in this study can be implemented into a user subroutine in the finite element (FE) software ABAQUS. Finally, the numerical results for E-shaped energy dissipation devices in the seismic isolation system are compared with the experimental test results so as to check the validity of the proposed model.

Background and study aims: Endoscopic surgical technology has been developing rapidly. Although several successful endoscopic closure devices have already been introduced, only a few of them have demonstrated improvements in closure strength and reproducibility over conventional endoscopic clip closures or hand sutures. The objective of this study was to test the feasibility of a novel successive suturing device (SSD) by measuring closure strength and reproducibility. Material and methods: Porcine stomach models were used in this study. Endoclips, full-thickness hand sutures, and the novel SSD sutures were used to close a perforation in the stomach wall, with 10 stomachs being tested for each closure method. Endoclips and SSD sutures were performed using a two-channel endoscope, and the hand sutures were performed from outside of the stomach wall. Air leakage pressure was measured to determine the closure strength and reproducibility of each method. Results: The mean air leakage pressure of the SSD closure was 62.7 ± 8.2 mmHg. SSD-treated stomachs exhibited significantly greater air leakage pressure than Endoclip-treated stomachs. The standard deviation of bursting pressure in SSD stomachs was found to be significantly smaller than that of hand-sewn stomachs but was not different from that of Endoclip stomachs. Conclusions: The consistent closure strength of SSD stomachs demonstrated the reliability and reproducibility of this new closure method. These promising results in closure strength and reproducibility suggest the feasibility of the proposed device for clinical applications.

Large deformation problem under dynamic loading has been an issue for mechanical engineer and researcher who study continuum mechanics because of its complex behavior. This study focuses on a large deformation problem based on nonlinear viscoplasticity. Therefore, the Johnson-Cook constitutive model and the Zerilli-Armstrong constitutive model are used to analyze and to understand this stretch example under dynamic loading. Numerical results for stretch example using both constitutive models were compared with the results from ABAQUS/Explicit that considered mesh sensitivity analysis, and were then applied to model failure processes of OFHC copper, with consideration of geometric nonlinearity based on concepts of progressive damage mechanics. This approach helps us to understand and to predict the behavior of large deformation and to perform damage failure analysis.

The objective of this study is to develop a new constitutive model for cyclic response of metals with much broader applicability. Accordingly, a two-surface damage thermoplasticity model is proposed to understand inelastic behavior and to evaluate a potential damaged state of the metals. This model, which derived from small strain theory, is formulated through a thermodynamic approach to damage mechanics based on entropy production. A simple shear problem was utilized to examine several effects of this model, such as fatigue by cyclic loading and temperature, and to allow for the thermal effects on metals. Following this, the proposed cyclic damage model is implemented as a user subroutine in the finite element software ABAQUS. Finally, numerical results of energy dissipation devices are compared with experimental data for validity of this model.

In real world applications, the response of structures may be dependent on the rate of loading and thus can be affected by transient loading, especially when the rate of loading is significant. In such situations, the rate of loading may become a major issue to understand structures during earthquake excitation or under blast or high velocity impact. In some cases, the rate effect on structures under strong earthquake excitation cannot be ignored when attempting to understand inelastic behavior of structures. Many researchers developed the constitutive theories in cyclic plasticity and viscoplasticity. In this study, numerical simulation by cyclic visocoplasticity models is introduced and analyzed. Finally, the analytical results are compared with experimental results as a means to evaluate and verify the model.

Various liquid scintillators are commonly used in neutrino experiments. If successful neutrino experiments are to be performed over several years, using stable solvents with the capability of mass production in the liquid scintillator is one of the key requirements. We investigate the various physical and optical properties, absorption, light transmission, light output, density, index of refraction, water content, etc., of the solvents used in neutrino detectors. In addition, safety for the environment and humans needs to be taken in consideration. In this paper, the preparation and the various characteristics of the solvents used for the liquid scintillator are summarized and reported.

Occurrence of frequency of earthquakes around the world has been increased including Sendai earthquake in Japan and magnitude of earthquake has also increased. Recently, many tall buildings using local seismic codes can be exposed to the risk of an earthquake and wind. Also, some buildings, which was planned to be built, were foundered as a result of lack of finance. Therefore, for tall buildings, structural safety such as earthquake and wind resistant performance, and financing issue are very important to progress the huge project. So we need to find another optimum alternative other than damping devices and base isolation system. In this study, four types of test specimens are used, which are fifty-story base tall building, tall building that was reinforced with diagonal brace, x-brace, and Chevron brace. And all of these cases, are subjected to the seismic load and wind load, finally analyzed and compared for seismic and wind performances.

The ICCASCE 2015 conference covers a wide range of fields in science and engineering innovation and aims to bring together engineering technology expertise. Scientists, scholars, engineers and students from universities, research institutes and industries all around the world gathered to present on-going research activities. This proceedings volume

Superelastic shape memory alloy materials have become increasingly prevalent for recentering devices that have the ability to recover their plastic deformation automatically. For this reason, this study proposed new clip-angle connections incorporating superelastic shape memory alloy bolts. Including component spring models, mechanical joint models of steel bolted connections and shape memory alloy bolted connections are created for numerically simulating their cyclic behavior. The numerical analysis results are then compared to each other in terms of ultimate strength, energy dissipation, and permanent deformation. In particular, over 60% of the total displacement was recovered during unloads in case of shape memory alloy bolted connections, indicating that the proposed smart connections display obvious recentering features in their behaviors.

This study deals with the experiments of liquid dampers with multi cells whose vertical tubes are divided into several square columns for easily changing natural frequencies. Shaking table test is performed to verify control effectiveness of the dampers which are installed on a building structure. To design liquid dampers, a 64-story building structure is reduced to a SDOF structure with 1/20 of similitude laws based on acceleration. The structure model is made up to adjust its mass and stiffness easily, with separate mass and drive parts. Mass parts indicate real structure`s weights and drive parts indicate real structure`s stiffness with springs and LM guides. Manufactured liquid damper has 18 cells and its natural frequency ranges are 0.65Hz to 0.81Hz. Shaking table test is carried out with one way excitation to compare with only accelerations of a large-scale structure and a structure installed with liquid dampers. Control performance of the liquid damper is expressed by the transfer function from shaking table accelerations to the large-scale structure ones. Testing results show that the liquid damper reduced a large-scale structure`s response by tuned natural frequencies.

Buckling-restrained braced frames are steadily replacing concentrically braced frames because buckling-restrained brace can yield without buckling when subjected to both tension and compression. Though buckling-restrained brace frames are being widely used as framing structures for construction in high seismicity areas, it is shown that at large strains, a considerable amount of permanent deformation is produced at the support connector between the brace and the frame. This drawback can be overcome by providing recentering capabilities to the braced frame system. By applying the concept of a recentering system to the design of buckling-restrained brace frames, we developed braced frames that incorporate buckling-restrained braces with superelastic shape memory alloy end-support connectors. Owing to the recentering capability, shape memory alloy materials have been used in the place where large deformation may feasibly occur. The primary advantages of the innovative braced frames proposed herein are verified through nonlinear pushover analyses. Analytical frame models are developed to estimate theultimate and residual inter-story drifts. The analysis results suggest that buckling-restrained brace frames with superelastic shape memory alloy bracing systems are more effective in controlling residual inter-story drifts than those with conventional steel bracing systems owing to the inherent self-healing characteristics of superelastic shape memory alloys.

In this study, a two surface plasticity model was developed and used to simulate the uniaxial ratchetting response of CS 1026 steel. Most cyclic plasticity models used in ratchetting simulations are Chaboche-type nonlinear kinematic hardening models, which deal with dynamic recovery terms considering the back stress tensor. This paper describes the ratchetting simulation of steel by the two surface model based on yield theory following both isotropic and kinematic hardening rules in order to obtain enhanced ratchetting response. The parameters used in the simulation were obtained from a parametric study and were determined from the initial range and stabilized range of CS 1026 steel. In addition, the two surface model was validated by comparing the results of a ratchetting simulation with experimentally determined maximum axial strain per cycle. The ratchetting responses obtained from the two surface model are an improved simulation results compared with results from bilinear and kinematic hardening models.

With the development of ICT technology, the broadcasting and communication networks of Korea have been bigger, faster and more reliable and Korea has become one of the leading countries in the ICT industry. Through the international ICT indices, we can see different economies' ICT industry competitiveness at a glance and high ranking in such indices can make national brand image improve. However almost all the existing international ICT indices mainly focused on the telecommunication industry, not on the broadcasting industry. This study thus aims to develop a new index focusing on broadcasting and communication networks. This new index is composed of 3 sectors such as access, usage and environment with different weight respectively and using objective indicators. This study also aims to contribute to improve Korea's national brand image by developing new systematic and effective broadcasting and communication index.

Experimental investigations on the atomization characteristics of twin-fluid water mist nozzle were conducted using particle image velocimetry (PIV) system and particle motion analysis system (PMAS). The twin-fluid water mist nozzles with swirlers designed two types of swirl angles such as 0°, 90° and three different size nozzle hole diameters such as 0.5mm, 1mm, 1.5mm were employed. The experiments were carried out by the injection pressure of water and air divided into 1bar, 2bar respectively. The droplet size of the spray was measured using PMAS. The velocity and turbulence intensity were measured using PIV. The velocity, turbulence intensity and SMD distributions of the sprays were measured along the centerline and radial direction. As the experimental results, swirl angle controlled to droplet sizes. It was found that SMD distribution decreases with the increase of swirl angle. The developed twin-fluid water mist nozzle was satisfied to the criteria of NFPA 750, Class 1. It was proven that the developed nozzle under low pressures could be applied to fire protection system.

This study presents the development of refined three dimensional (3D) finite element (FE) models with the ability to reliably simulate the mechanical behavior of full-scale bolted T-stub connections. FE models incorporated material nonlinearity, geometric nonlinear behavior, several contact interactions between faying surfaces, and prescribed displacements for generating initial bolt pretension. These FE models were used to compare experimental test results, which verify that advanced FE modeling methods make a notable contribution to reproducing the overall behavior of connections and components accurately, including the moment-rotation curves. In addition, the FE models provide some useful information which is difficult to obtain during physical testing, i.e., the distribution of stress and strain, friction forces between shear faying surfaces, and bolt reaction forces. The validated FE models are also used for additional parametric studies so as to comprehensively understand their response mechanisms. Moreover, the observation of FE analysis results supports the statement that connection models presented herein were designed to reach the yielding of connection components when the structural beam produces its full plastic moment at the plastic hinge.

A tunable Fabry-Perot interferometer (TFPI)-type wavelength filter designed for the long-wavelength infrared (LWIR) region is fabricated using micro electro mechanical systems (MEMS) technology and the novel polydimethylsiloxane (PDMS) micro patterning technique. The structure of the proposed infrared sensor consists of a Fabry-Perot interferometer (FPI)-based optical filter and infrared (IR) detector. An amorphous Si-based thermal IR detector is located under the FPI-based optical filter to detect the IR-rays filtered by the FPI. The filtered IR wavelength is selected according to the air etalon gap between reflectors, which is defined by the thickness of the patterned PDMS. The 8 &mu, m-thick PDMS pattern is fabricated on a 3 nm-thick Al layer used as a reflector. The air etalon gap is changed using the electromagnetic force between the permanent magnet and solenoid. The measured PDMS gap height is about 2 &mu, m, ranging from 8 &mu, m to 6 &mu, m, with driving current varying from 0 mA to 600 mA, resulting in a tunable wavelength range of 4 &mu, m. The 3-dB bandwidth (full width at half maximum, FWHM) of the proposed filter is 1.5 nm, while the Free Spectral Range (FSR) is 8 &mu, m. Experimental results show that the proposed TFPI can detect a specific wavelength at the long LWIR region.