• Title/Summary/Keyword: trade-off study

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A Study on the Development of Guide to Overcome Risks When Buying Wines (와인 구매 리스크 극복을 위한 가이드 개발 방안에 관한 연구)

  • Yoon, Yong;An, Oug Hyun;Kim, Youn Sung
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.5 no.4
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    • pp.753-760
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    • 2015
  • The Korean wine market is growing year by year recently especially in Off-trade market. It shows not just a part of the very few consumer-driven trend. The purchases of wine is always not so easy because the risk factors and failure points occur when buying wines. Most of wine consumers feel difficulties when buying wines at phase of previous step, buying step and after buying step. Wine consumers can be divided into the wine experts, wine lovers, novices, outsiders. To guide an wine buying with less failures to each representative of wine consumer characteristics and needs, user persona and scenario for the reduced failure were derived.

The effect of thinning on trade-offs in ecosystem services: the case study of a Korean pine plantation on Mt. Gari

  • Kiwoong Lee;Soon Jin Yun;Minsoo Kim;Hee Moon Yang;A Reum Kim
    • Journal of Ecology and Environment
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    • v.48 no.2
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    • pp.137-143
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    • 2024
  • Background: The study was carried out to analyze the temporal changes of trade-offs (TOs) between two ecosystem services (ESs) before and after thinning in a Pinus koraiensis plantation on Mt. Gari from 2006 to 2021. As target variables, aboveground carbon (AGC) storage and species richness (SR) were chosen for regulating and supporting services. Thinning was applied from 2007 through 2008 with three treatments: 1) light thinning (LT), 2) heavy thinning (HT), and 3) control (Con). Results: Thinning influenced both AGC and SR. In 2021, AGC in the Con (111.1 t C ha-1) was significantly higher compared to the LT (82.0 t C ha-1) and HT (60.4 t C ha-1) after thinning from 2007 to 2008. Also, SR was marginally higher in the LT (94 species) than in the Con (55 species) and HT (87 species) in 2011. Relative benefits of AGC and SR showed similar trends with the obtained values. In addition, the effects of thinning on TO varied among treatments and over time, demonstrating different degrees of TO between the two ESs. In the LT, TO was 0.13 in 2006 and slightly increased to 0.2 by 2021. TO in the HT exhibited a relatively rapid increase from 0.22 in 2006 to 0.58 by 2021, while To in the Con fluctuated, rising to 0.36 in 2011 from 0.1 in 2006 and decreasing to 0.25 by 2021. Among the three treatments, the degree of TOs between the two ESs was the lowest in the LT. Conclusions: Depending on thinning intensities, the responses of ESs and the degree of TOs vary. Regarding the balance between enhancements and TOs in ESs among treatments, the LT treatment showing intermediate carbon storage, higher SR, and lower TOs will be a proper silvicultural application.

A Study on the Combustion Optimization of a Common Rail Direct Injection Diesel Engine for Regeneration of the Diesel Particulate Filter (매연여과장치 재생을 위한 커먼레일 디젤엔진의 연소 최적화에 관한 연구)

  • Kang Jung Whun;Kim Man Young;Youn Gum Joong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.4
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    • pp.167-173
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    • 2005
  • Thermal regeneration means burning-off and cleaning-up the particulate matters piled up in DPF(diesel particulate filter), and it requires both high temperature $(550\~600^{\circ}C)$ and appropriate concentration of oxygen at DPF entrance. However, it is not easy to satisfy such conditions because of the low temperature window of the HSDI(high speed direct injection) diesel engine(approximately $200\~350^{\circ}C$ at cycle). Therefore, this study is focused on the method to raise temperature using the trade-off relation between temperature, oxygen concentration, and the influence of many parameters of common rail injection system including post injection. After performing an optimal mapping of the common rail parameters for regeneration mode, the actual cleaning process during regeneration mode is investigated and evaluated the availability of the regeneration mode mapping through regenerating soot trapped in the DPF.

Achieving Maximum System Throughput with Cooperative Relaying: A Case Study of IEEE 802.16j Multi-Hop Relay

  • Ryu, Hyun-Seok;Lee, Hee-Soo;Ahn, Jae-Young;Kang, Chung-Gu
    • Journal of Communications and Networks
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    • v.12 no.5
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    • pp.466-474
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    • 2010
  • Various types of cooperative relaying (CR) schemes exhibit different levels of throughput and outage performance because of their inherent trade-off between diversity gain and opportunity cost; in other words, the overhead that is associated with cooperation. This article attempts to answer whether cooperative communication is beneficial or not from the system-level viewpoint and furthermore, if it is, how its average throughput can be maximized while maintaining the target outage rate. In order to improve throughput at the required outage performance, we propose a unified selection criterion to deal with different levels of combining gain and opportunity cost associated with each scheme, which allows for the employment of different CR schemes for various positions of the mobile station. Our system-level simulation results for an IEEE 802.16j multi-hop relay confirm the varying levels of trade-offs among different CR schemes and furthermore, show that CR will be a useful means of maximizing the average throughput for a multi-hop relay system as long as each type of the cooperating scheme is carefully selected, depending on the position of the mobile stations.

A Study on Optimized Size of a Mobile Harbor for South Korea Coastal Service

  • Heo, Sung-Kuk;Park, Nam-Kyu
    • Journal of Navigation and Port Research
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    • v.35 no.2
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    • pp.159-165
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    • 2011
  • The aim of paper is to calculate the optimized size of Mobile Harbor(MH) which would be operated in South Korea coast area. MH is the combined entity which has the function of both ship and container port. In estimating the optimized size, the total cost concept is applied to the different size of MH. Trade-off factors for calculating total cost are MH cost and the over-capacity lost cost. The factors for MH cost estimation are the cargo demand, distance from origin to destination, voyage route and MH's fixed and variable cost in both sailing and port. The other cost is the over-capacity lost cost which is occurred from dead space in case of oversize compared with a voyage demand. The alternatives for the least cost are 250TEU, 500TEU, 750TEU and 1,000TEU sized vessel. The result of research is that 250TEU sized vessel is optimized in a South Korea costal service. If the coastal area be separated in terms of voyage distance or the specific area in considering trade, the optimized size is changed depending upon distance.

Effects of Feedback Types on Writing Accuracy, Fluency, and Complexity

  • Park, Chongwon
    • English Language & Literature Teaching
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    • v.17 no.4
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    • pp.207-227
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    • 2011
  • This paper investigates how two different modes of feedback (selective vs. comprehensive) affect selected students' writing development in terms of three different types of measurement (accuracy, fluency, and complexity). 139 university students participated in the study, and 278 writing samples were analyzed. The results of the study indicate that participants who received selective feedback wrote more accurately and fluently than their counterparts. However, in terms of complexity, both selective and comprehensive groups showed no sign of improvement in semester-based investigations. The results of this study support Skehan's (2009) theory of trade-off effects, suggesting that 'natural' tension exists between accuracy and complexity when resources are limited. Moreover, this finding contrasts with the theory of Cognition Hypothesis, which proposes that task complexity will be associated with increases in complexity and accuracy. In the study, selected participants (N=21) strongly nominated their error sources as unfamiliarity toward using key words, usage, transition, and sentence types. This study not only contributes to the accumulation of our current knowledge in the related area of theory, but offers educational implications for those who are dealing with intermediate-level students when deciding what particular teaching content should constitute a priority within a limited instructional period.

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Decision Support Tool for Excavation Operation using Genetic Algorithms

  • Lee, Ung-Kyun;Kang, Kyung-In;Cho, Hun-Hee
    • Architectural research
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    • v.8 no.2
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    • pp.43-48
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    • 2006
  • The appropriate fleet estimation of the excavation equipment is a major factor in the determination of the cost and time requirements of a project. But the decision of what kind of equipment selected is often based on heuristic methods or trial and error in Korea. Thus, this study proposes a prototype model that uses genetic algorithms to select fleet estimation of loaders (backhoe) and trucks used in excavation work. To verify the applicability of this model, the case study was performed. And the result of the genetic model was compared with that of the trial & error method. The use of the genetic model suggested this study required 44days, 2 units of backhoes, 7 units of trucks, and a total cost of 171,839,756 won. With the estimated fleet number of equipment, the minimum cost of excavation work can be calculated, taking account of the time-cost trade-off. By utilizing this prototype model, the efficiency of excavation work can be improved.

A Study on Cost-Benefit Analysis for Value of Preventing a Statistical Fatality (개인생명가치추정을 통한 안전개선 비용효과 분석에 관한 연구)

  • Park Chan-Woo;Kim Sang-Am;Wang Jong-Bae;Hong Seong-Ho;Kwak Sang-Log
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.186-191
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    • 2004
  • Whenever some new measure to promote safety is being considered, one major input into the decision making process is to be some formal assessment of the costs and benefits involved. What levels of safety do many stakeholders believe the railway should deliver? This paper is a contribution to the efforts to answer the question. In this study, under Willing-To-Pay(WTP) based value of preventing a fatality(VPF) approach, we will study how much people are willing to trade off safety against other desirable things, summarize accepted quantitative criteria for safety quantitative criteria for safety decision, describe differences between these criteria and some current risk control actions, and present an outline of work under way to address issues related to cost-benefit analysis(CBA).

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Experimental study on the fatigue performance of aluminum foam sandwich with 304 stainless steel face-sheet

  • Yan, Chang;Jing, Chuanhe;Song, Xuding
    • Steel and Composite Structures
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    • v.39 no.3
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    • pp.229-241
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    • 2021
  • This work focused on aluminum foam sandwich (AFS) with different foam core densities and different face-sheet thicknesses subjected to constant amplitude three-point bending cyclic loading to study its fatigue performance. The experiments were conducted out by a high frequency fatigue test machine named GPS-100. The experimental results showed that the fatigue life of AFS decreased with the increasing loading level and the structure was sensitive to cyclic loading, especially when the loading level was under 20%. S-N curves of nine groups of AFS specimens were obtained and the fatigue life of AFS followed three-parameter lognormal distribution well. AFS under low cyclic loading showed pronounced cyclic hardening and the static strength after fatigue test increased. For the same loading level, effects of foam core density and face-sheet thickness on the fatigue life of AFS structure were trade-off and for the same loading value, the fatigue life of AFS increased with aluminum foam core density or face-sheet thickness monotonously. Core shear was the main failure mode in the present study.

A Study on the Theory of Overseas Direct Investment (해외직접투자이론(海外直接投資理論)에 관한 소고(小考))

  • Bin, Bong-Sik
    • The Korean Journal of Financial Management
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    • v.1 no.1
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    • pp.119-131
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    • 1985
  • Although Korea is short of capital technology, and natural resources, she has achieved an outstanding progress by the export-drive policies by Korean government and the creative endeavor of Korean firms. As a result of that, Korean economy and enterprises are in the same file of newly industrialized countries and Korea is ready for an economic take-off as a developed country. But in the early 1980s, each country strengthens protective trade theory and resources nationalism, and this has a great influence on the field of international trade environment. In spite of that, to continue the same high development as that of the past. Korea must try to secure and find export markets, solve trade barriers, make sure of the long-term security of resources, develop technology, and strengthen economic cooperations. To satisfy these desires by 2000s, we must try to make Korean enterprises have the global competitive power and them grow strongly among world wide firm through capital and technology accumulated during the passed years, and to do so, there must be a foreign production and marketing management, too, this can be achieved only through foreign overseas direct investment. This investment has various forms, to say, verifical integrated, horizontal integrated. conglomerate integrated forms, and the amount of investment in each country from 18 century to today reaches 500 billion dollars. This investment is done by strategic, behavioral economic, and financial motives. So I am going to approach the fields of like these; in spite of the differences among political, economical, caltural, and social systems, and many risk compared with domestic enterprises, why do Korean firms witsh to transfer the productive facilities to overseas countries and run them there? What is the comparative advantage of foreign direct investment compared with domestic investment ?. why is the factor of comparative advantage transferred through foreign direct investment?, what is the motive of foreign overseas direct investment?, and last the ownership-specific factors and the theory of internalization, and the location specific factors were analysed chiefly. But in consideration of the given condition in Korea, Korean overseas direct investment must be propelled rationally on the basis of the above mentioned theory.

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