• Steel and Composite Structures
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• 제1권2호
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• pp.171-185
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• 2001

The design of tall buildings has recently provided many challenges to structural engineers. One such challenge is to minimise the cross-sectional dimensions of columns to ensure greater floor space in a building is attainable. This has both an economic and aesthetics benefit in buildings, which require structural engineering solutions. The use of high strength steel in tall buildings has the ability to achieve these benefits as the material provides a higher strength to cross-section ratio. However as the strength of the steel is increased the buckling characteristics become more dominant with slenderness limits for both local and global buckling becoming more significant. To arrest the problems associated with buckling of high strength steel, concrete filling and encasement can be utilised as it has the affect of changing the buckling mode, which increases the strength and stiffness of the member. This paper describes an experimental program undertaken for both encased and concrete filled composite columns, which were designed to be stocky in nature and thus fail by strength alone. The columns were designed to consider the strength in axial compression and were fabricated from high strength steel plate. In addition to the encased and concrete filled columns, unencased columns and hollow columns were also fabricated and tested to act as calibration specimens. A model for the axial strength was suggested and this is shown to compare well with the test results. Finally aspects of further research are addressed in this paper which include considering the effects of slender columns which may fail by global instabilities.

• KIEAE Journal
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• 제10권1호
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• pp.65-72
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• 2010

The use of natural light has the potential for improving both the energy efficiency and indoor environmental quality in buildings. A light-pipe system can introduce daylight to spaces that would otherwise not be able to benefit from the advantages of daylight penetration. For the light-pipe system to be widely used in Korea, it is important to quantify its daylighting performance with due consideration regarding the effects imposed by the local climate conditions. This paper presents the evaluation results of existing semi-empirical models to predict daylighting performance of a light-pipe system. The evaluation of the existing models was based on the monitoring data obtained from a underground parking lot in which the light-pipe system was installed. Comparisons were made between the predicted and the monitored data obtained from the study. The results indicated that semi-empirical models which was developed using the experimental data obtained under the Korean climatic conditions had a good prediction performance. We also quantified the effects caused by sky conditions, solar altitudes, room dimensions, and the aspect ratio of a light-pipe system on both the daylighting performance of the light-pipe system and the indoor illuminance distributions of the space using the semi-empirical model. Finally, this paper provides the design guideline of the light-pipe system for its application to an underground parking lot space.

• 전기학회논문지
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• 제58권5호
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• pp.960-967
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• 2009

Power supply system of electric railway has a diversity of safety problems since it should supply high electric power to the trains moving high speed with a lot of passengers on board. This paper provides a risk assessment approach to safety management of the electric railway facilities. Construction of database from field accident information, risk assessment and management of the risk are carried out systematically to ensure the safety. The risk assessment includes hazard identification, cause analysis by FTA(Fault Tree Analysis), consequence analysis by EVA(Event Tree Analysis), and loss analysis. In terms of the severity and the probability of the accidents deduced by these analyses, the risk of the accidents is assessed by using a risk matrix designed for electric railway facilities. Based on the risk assessment, possible risk mitigation options are identified and evaluated by analyzing their impact on the risk reduction and their cost benefit ratio. The long-term safety of the electric railway facilities can be ensured by renewal of the risk assessment and the risk mitigation option analysis with continuous accident database update. The proposed approach is applied to the electric railway facilities of Korean railway based on the accident data from 2002 to 2008.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2011년도 제45차 학술발표회
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• pp.35-35
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• 2011

Phase change material(PCM) has thermal energy storage and been attracted attention. Latent heat of the organic PCM can keep maintaining temperature when the change of outside energy conditions influence to PCM. Thus, many researchers have interested to thermal energy storage ability and investigated to applications such as thermal storage of solar energy, bioclimatic building, icebank, medical application, clothing industry and so on. Among the many applications, investigation of the PCM in clothing industry is also important because the people has interest functional factor called health-care in the clothing. In addition, PCM can give them mild environment condition such suitable temperature control or humidity. To fabrics, the PCM has various methods such as microcapsule, padding and modified cross-section formation(Sheath/core). Sheath core PCM fabric has a better benefit of durability than other method. However, PCM sheath/core spinning is difficult. In addition, dyeing property is important to use clothing industry due to visual images. In this study, we investigated dyeing properties of Nylon/PCM sheath/core fabrics. Especially, we observed the relation between dyeing property and PCM including ratio. Various temperature and pH conditions were also studied to optimize dyeing properties as acid dye.

• Radiation Oncology Journal
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• 제35권4호
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• pp.359-367
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• 2017

Purpose: This study sought to identify potential candidates for adjuvant radiotherapy and patterns of regional failure in patients who underwent curative-intent surgery for gallbladder cancer. Materials and Methods: Records for 70 patients with gallbladder cancer who underwent curative resection at a single institution between 2000 and 2016 were analysed retrospectively. No patients received adjuvant radiotherapy. Initial patterns of failure were evaluated. Regional recurrence was categorized according to the definitions of lymph node stations suggested by the Japanese Society of Hepato-Biliary-Pancreatic Surgery. Results: Median follow-up was 23 months. Locoregional recurrence as any component of first failure occurred in 29 patients (41.4%), with isolated locoregional recurrence in 13 (18.6%). Regional recurrence occurred in 23 patients, and 77 regional recurrences were identified. Commonly involved regional stations were #13, #12a2, #12p2, #12b2, #16a2, #16b1, #9, and #8. Independent prognostic factors for locoregional recurrence were ${\geq}pT2$ disease (hazard ratio [HR], 5.510; 95% confidence interval [CI], 1.260-24.094; p = 0.023) and R1 resection (HR, 6.981; 95% CI, 2.378-20.491; p < 0.001). Conclusion: Patients with pT2 disease or R1 resection after curative surgery for gallbladder cancer may benefit from adjuvant radiotherapy. Our findings on regional recurrence may help physicians construct a target volume for adjuvant radiotherapy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.3056-3074
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• 2014

Convergecast is probably the most common communication style in wireless sensor networks (WSNs). And linear network coding (LNC) is a promising concept to improve throughput or reliability of convergecast. Most of the existing works have mainly focused on exploiting these benefits without considering its potential adverse effect. In this paper, we argue that LNC may not always benefit convergecast. This viewpoint is discussed within four basic scenarios: LNC-aided and none-LNC convergecast schemes with and without automatic repeat request (ARQ) mechanisms. The most concerned performance metrics, including packet collection rate, energy consumption, energy consumption balance and end-to-end delay, are investigated. Theoretical analyses and simulation results show that the way LNC operates, i.e., conscious overhearing and the prerequisite of successfully decoding, could naturally diminish its advantages in convergecast. And LNC-aided convergecast schemes may even be inferior to none-LNC ones when the wireless link delivery ratio is high enough. The conclusion drawn in this paper casts a new light on how to effectively apply LNC to practical WSNs.

• The Journal of Asian Finance, Economics and Business
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• 제8권12호
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• pp.85-94
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• 2021

Infrastructure capacities are essential elements and one of the sustainable lines to drive economic growth. Infrastructure development, both physical and social, is vital to sector-wise economic development. However, there is limited evidence of how infrastructure development in certain sectors benefits the economy as a whole. This study explains the relationships between infrastructure and economic growth in selected middle-income Asian countries, highlighting the essential criteria to benefit from both physical and social infrastructure, as well as sectoral (agriculture, industry, and services) economic output. The research uses the data from 1990 to 2020 for empirical estimations. The study used Levin, Lin, & Chu test, ADF- Fischer chi- Square, and PP- Fischer Chi-Square to test unit root and to observe the stationary nature of the panel. Padroni and Kao cointegration is applied to check the cointegration among different panes. A Fully Modified OLS was employed for checking the association between physical and social infrastructure and economic growth. Results show that physical and social infrastructure negatively impact sectoral output in Asia's middle-income countries. Apart from infrastructure the per capita GDP growth, tax to GDP ratio, and population growth shows a simultaneous relation between infrastructure and sectoral economic growth.

• 수산경영론집
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• 제52권2호
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• pp.33-54
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• 2021

This study is aimed to analyze the economic feasibility of yellowtail culture using the copper alloy net cage in Gyeongsangbuk-do. First of all, in order to evaluate the copper alloy net cage on yellowtail culture, I review the trend on the yellowtail culture industry and research the concept of copper alloy net cage. The copper-alloy net cage is now recognized as an advantages of its system stability, recycling, antibiosis and food safety. The results were summarized as follows: first, there was significant meaning of the profit model of yellowtail culture by the price difference. Second, I analyzed in the economic feasibility of yellowtail culture using the copper alloy net cage, internal rate of return (IRR) was 51.58%, a benefit-cost ratio was shown to be 2.27 and net present value (NPV) was 1,087,337 thousand won, which indicates the economic feasibility of yellowtail culture using the copper alloy net cage is profitable. Finally, in order to improve the economic valuation, it is necessary to focus more on the developing of technology and cost reduction strategy on the copper alloy net cage.

• Journal of Obesity & Metabolic Syndrome
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• 제27권4호
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• pp.213-222
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• 2018

Bariatric surgery has evolved from a surgical measure for treating morbid obesity to an epochal remedy for treating metabolic syndrome as a whole, which is represented by type 2 diabetes mellitus. Numerous clinical trials have advocated bariatric or metabolic surgery over nonsurgical interventions because of markedly superior metabolic outcomes in morbidly obese patients who satisfy traditional criteria for bariatric surgery (body mass index [BMI] >$35kg/m^2$) and in less obese or simply overweight patients. Nevertheless, not all diabetes patients achieve the most desirable outcomes; i.e., diabetes remission after metabolic surgery. Thus, candidates for metabolic surgery should be carefully selected based on comprehensive preoperative assessments of the risk-benefit ratio. Predictors for diabetes remission after metabolic surgery may be classified into two groups based on mechanism of action. The first is indices for preserved pancreatic beta-cell function, including younger age, shorter duration of diabetes, and higher C-peptide level. The second is the potential for an insulin resistance reduction, including higher baseline BMI and visceral fat area. Several prediction models for diabetes remission have been suggested by merging these two to guide the joint decision-making process between clinicians and patients. Three such models, DiaRem, ABCD, and individualized metabolic surgery scores, provide an intuitive scoring system and have been validated in an independent external cohort and can be utilized in routine clinical practice. These prediction models need further validation in various ethnicities to ensure universal applicability.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권2호
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• pp.8-22
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• 2019

Among numerous chemicals used globally, the number of emerging contaminants is increasing. Numerical modeling for contaminant fate and transport in the subsurface is critical to evaluate environmental and health risk. In general, such models require physicochemical properties of contaminants as input values, which can be found in numerous chemical databases (DB). However, there exist lack of information specific to recently emerging contaminants, which requires estimation of physicochemical properties using regression programs. The purpose of the study is to introduce the workflow for identifying physicochemical properties of potential contaminants utilizing numerous chemical DBs, which frequently lists up potential contaminants for estimating chemical behavior. In this review paper, details of several chemical DBs such as KISChem, TOXNET, etc. and regression programs including EPI $Suite^{TM}$, ChemAxon, etc. were summarized and also benefit of using such DBs were explained. Finally, a few examples were introduced to estimate predominant phase, removal ratio, partitioning, and eco-toxicities by searching or regressing physicochemical properties.