• Journal of Korean Society of Steel Construction
• /
• v.19 no.1
• /
• pp.15-27
• /
• 2007

Over the past decade, labor costs have increased relative to the cost of material hardware according to analysts in the construction industry. Therefore, the minimum weight design, which has been widely adopted in the literature for the optimal design of steel structures, is no longer the most economical construction approach. Presently, although connection- related costs is crucial in determining the most cost-effective steel structures, most studies on this subject focused on minimum-weight design or engaged in higher analysis. Therefore, in this study, we proposed a fabrication scheme for the most cost-effective moment-resisting steel frame structures that resist lateral loads without compromising overall stability. The proposed approach considers the cost of steel products, fabrication, and connections within the design process. The optimal design considered construction realities, with the optimal trade-off between the number of moment connections and total cost was achieved by reducing the number of moment connections and rearranging them using the combination of analysis that includes shear, displacement and interaction value based on the LRFD code and optimization scheme based on genetic algorithms. In this study, we have shown the applicability and efficiency in the examples that considered actual loading conditions.

• Health Policy and Management
• /
• v.17 no.4
• /
• pp.113-133
• /
• 2007

The present study was conducted to measure health-related utility for post-menopausal symptoms among Korean woman. A survey questionnaire was developed to measure utility based on visual analogue scale(VAS) and time trade-off method (TTO). From January 29 to February 3, 2007, a face-to-face interview was conducted with 274 women aged 45 to 60 to ask about their subjective utility for hypothetical health status of mild or severe post-menopausal symptoms. Among the participants, 160 were recruited from outpatient departments of 3 hospitals and 114 from 2 sports centers located in Seoul. For mild symptom, the average utility score of the respondents was $0.63{\pm}0.14$ based on VAS and $0.61{\pm}0.26$ based on ITO. For severe symptoms, the average utility was $0.39{\pm}0.16$(VAS) and $0.44{\pm}0.27$ (TTO). For severe symptom, a higher utility score was observed for TTO than for VAS, which is consistent with earlier studies and thus supports the validity of the utility measurement in this study. Overall, the severity of post-menopausal symptoms of the respondents themselves was not significantly associated with the utility score that the respondents answered for hypothetical health status. Multiple regression analysis results showed that the utility score was significantly higher among respondents with older age, higher education, higher family income, and from hospitals. It is expected that the utility score measured in this study will enhance the understanding of the quality of life of women after menopause and will be used to conduct cost-utility analysis of health care interventions to treat post-menopausal symptoms.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.255-263
• /
• 2016

This study conducted empirical tests on contemporary finance theories for corporate cash holdings, such as trade-off, pecking order, and agency theory. There is ongoing debate on the possibility of excess cash savings by domestic firms, including chaebols in the Korean capital markets. Thus, it may be worthy to identify any financial characteristics based on each aforementioned theory as an extension of previous studies on similar subjects. Two primary hypotheses were postulated and tested, and the following empirical results were obtained. First, principal component analysis (PCA) provides evidence that nine out of the twenty explanatory variables showed a significant influence on the level of corporate cash holdings, such as cash conversion cycle in trade-off theory and leverage in pecking order theory. Second, the chaebol firms that decreased cash holdings after global financial turmoil may be affected by financial factors that include investment opportunities and foreign ownership according to the PCA. The results may reinforce the outcomes derived from previous research on corporate cash holdings. Based on the robust results, large firms in advanced or emerging capital markets could approach the optimal level of the cash reserves.

• The KIPS Transactions:PartD
• /
• v.18D no.5
• /
• pp.371-384
• /
• 2011

This paper considers logistics decision support system which deals with transportation mode selection considering transportation and carbon emission cost. Transportation and carbon emission costs vary with the choice of transportation modes and to become competitive companies need to find proper transportation modes for their logistics services. However, due to the restricted capacity of transportation modes, it is difficult to balance transportation and carbon emission costs when designing logistics network including transportation mode choice for each service. Therefore this paper aims to analyze the trade-off relationship between transportation and carbon emission cost in mode selection of intermodal transportation and to provide optimal green logistics strategy. In this paper, the logistics decision support system is designed based on mixed integer programming model. To understand the trade-off relationship of transportation and carbon emission cost, the system is tested with various scenarios including transportation of containers between Seoul and Busan. The analysis results show that, even though sea transportation combined with trucking is competitive in carbon emission per unit distance travelled, the total cost of carbon emission and transportation for the sea transportation may not have competitive advantage over other transportation modes including rail and truck transportation modes. The sea-based intermodal logistics service may induce detours which have negative impacts on the overall carbon emission. The proposed logistics decision support system is expected to play key role in green logistics and supply chain management.

• 한국사회정책
• /
• v.24 no.4
• /
• pp.3-29
• /
• 2017

The study checked whether the trade-off relationship between the home ownerhip and welfare by Kemeny and Castles was still valid in four welfare regimes, and analysed the factors of change and stability on rate of home ownership between social democratic states and southern european states. Based on the results of the study, the relationship between housing ownership and public expenditure was confirmed only in the liberal welfare regime and in the conservative welfare regime, as evidenced by the 2014 data collection. Second, social democratic states have dramatically increased housing mortgage loans and showed signs of housing commodification but southern european states have showed pre commodification of housing, maintained comparatively whole home ownership and low mortgage loans. Third, social democratic states has resulted in a rise in housing demand and housing prices, through reduced new housing and social rented housing construction, home owenership friendly taxation and generous lending policies, but southern european states have maintained a stable housing demand and housing prices thanks to the rich housing stocks, extended family, self provision and self promotion by close relatives, and intergenerational inheritance and transfers of housing. Although sequence of the equity ownership and welfare are still unclear, it is not a rational alternatives to induce housing ownership through large mortgage loans.

• The Journal of Fisheries Business Administration
• /
• v.17 no.1
• /
• pp.107-115
• /
• 1986

The United States is the world's leading importer of frozen processed groundfish products, with over two thirds of total world imports. Over 90% of the U.S. groundfish demand is met by inports, while about 2 million mt of groundfish are taken from U, S. waters by joint-venture and foreign fleets. The objective of this paper is to provide descriptive information concerning the U.S. groundfish market and the potential for groundfish resources off Alaska to become a major source of supply to this market. The size of the U.S. market, U.S. imports, trade policies, and catch from U.S, waters are discussed, and a comparison is made between the potential domestic catch of groundfish off Alaska and current U.S. groundfish consumption. The total optimum yield of 2.3 million mt for flounders, cod, and pollock is about four times the round weight equivalent of U.S. imports of these species in 1984.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.17 no.3
• /
• pp.20-25
• /
• 1980

A singular value decomposition (SVD) pseudo-inversion method has been applied to the image reconstruction from projections. This approach is relatively unknown and differs from conventionally used reconstructioll methods such as the Foxier convolution and iterative techniques. In this paper, two SVD pseudo-inversion methods have been discussed for the search of optimum reconstruction and restoration, one using truncated inverse filtering, the other scalar Wiener filtering. These methods partly overcome the ill-conditioned nature of restoration problems by trading off between noise and signal quality. To test the SVD pseudo-inversion method, simulations were performed from projection data obtained from a phantom using truncated inversefiltering. The results are presented together with some limitations particular to the applications of the method to the general class of 3-D image reconstruction and restoration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.844-847
• /
• 2001

In this work, transient characteristics of the Non-Punch Through(NPT) Insulated Gate Bipolar Transistor(IGBT) has been studied. we has analyzed with lifetimes excess minority carrier injected into N-dirft, base region of IGBT's BJT part and accumulated charge of on-state which affected swiching characteristic. In this paper, excess minority carrier and charge distribution in active base region is expressed analytically. This analysis proposed optical trade-off between lifetimes and accumulated charge for decreasing switching losses because charge result in switching loss when device was tuned off.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.12
• /
• pp.122-129
• /
• 1995

The most important feature of a-Si TFT is dense localized states such as dangling bonds which exist in tis bandgap. Electrons trapped by localized states dominate the potential distribution in the active a-Si region ,and influence the performance of a-Si TFT. In this paper, we describe the electrical characteristics of a-Si TFT with respect to trap distribution within bandgap, electron mobility and interface states using 2-Dimensional device simulator and compare the result of simulation with measurements. Using the mixed-mode simulator, we can predict the potential variation of pixel which causes residual image problem during the turn-off of a-Si TFT driving circuit. Therefore it is possible to consider trade-off between potential variation of pixel and turn-on current of a-Si TFT for the optimized driving circuit.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.542-545
• /
• 2002

This paper deals with the optimization inverter design and minimization Conduced EMI noise by customizing IPM(Intelligent Power Module). Generally, In case of IPM, we realized that the trade-off relation between switching loss and spike voltage. Higher gate resistor causes tile lower spike voltage and the higher turn-off switching loss. But we know that the life cycle of inverter and the susceptibility of noise, so we optimized the gate resistor. Proposed method is that optimized the gate resistor suitable for the inverter and motor. The simulation and experimental results show that the spike voltage and Conduced EMI noise can be reduced without the additional circuit.