• 전기학회논문지
• /
• 제65권12호
• /
• pp.2251-2261
• /
• 2016

The use of renewable energy sources and energy storage systems is increasing due to new policies in the energy industries. However, the increase in distributed generation hinders the reliability of power systems. In order to stabilize power systems, a virtual power plant has been proposed as a novel power grid management system. The virtual power plant plays includes different distributed energy resources and energy storage systems. We define a core virtual power plant technology related to demand response and ancillary service for the cases of Korea, America, and Europe. We also suggest applications of the proposed virtual power plant to the vehicle-to-grid market for restructuring national power industries in Korea.

• 한국의상디자인학회지
• /
• 제10권2호
• /
• pp.163-178
• /
• 2008

The purpose of this study is to search the characteristics and strategy of sales promotion in on-line fashion SOHO (Small Office Home Office) shopping malls. 87 of these shopping malls have been selected through a ranking service called 100HOT (http://www.100hot.co.kr), and 906 cases of sales promotion activities have been executed on web-sites of these shopping malls. The cases have been analyzed by descriptive statistics and chi-square analysis. The results are as follows: First, on-line fashion SOHO shopping malls have frequently used sales promotion tactics such as demonstration, display, viral marketing, sale, event, customer compensation, community marketing, experimental marketing, coupon, premium, reserve fund and delivery service. Second, there are significant differences between shopping malls for men and women in sales promotion tactics such as demonstration, viral marketing, sale, and community marketing, but there is no significant difference in tactics such as demonstration, event, and customer compensation. Third, the shopping malls have used various sales promotion strategies such as maximizing the sales, characterizing product features, procuring new customers, preserving existing customers, enhancing customer loyalty, improving customer relationship and controlling returns.

• 한국조경학회지
• /
• 제45권2호
• /
• pp.40-50
• /
• 2017

수정된 IPA는 전통적 IPA와 비교시 실제 방문객 만족도가 반영된 관리전략을 수립하는데 있어 효과적인 방법이다. 그러나 전통적 IPA와 수정된 IPA의 비교연구는 제한적이다. 그러므로 본 연구에서는 순천만 습지 내 효과적인 관리전략을 구축하기 위해 전통적 IPA와 수정된 IPA를 비교분석하였다. 첫째, 수정된 IPA를 선정하기 위해 선행연구를 고찰하였고, 공간 내 방문객의 실제 만족도에 영향을 받는 관리전략과 서비스 질을 정량화 할 수 있는 적절한 방법으로 Deng(2007) 방법론을 선정하였다. 둘째, 순천만 습지 내 전통적 IPA와 수정된 IPA를 적용한 결과를 비교분석하였다. 셋째, 수정된 IPA의 관리전략과 변화된 관리요소에 관해 논의하였다. 그 결과, 전통적 IPA 결과보다 관리요구도가 더 높게 도출된 관리요소로 혼잡도가 나타났고, 관리요구도가 더 낮게 도출된 관리요소 중 집중관리에서 저우선순위로 관리전략이 변화하는 관리요소의 경우, 그늘목, 전시시설 내부, 프로그램, 가이드투어가 분석됐으며, 현 상태 유지에서 과잉노력지양으로 분석된 관리요소의 경우, 휴게시설, 낙조, 생울타리, 전시시설 외부로 도출되었다. 이는 현재 순천만 습지 내 관리전략과 비교시 전통적 IPA 결과값보다 수정된 IPA의 결과값에 더 부합된 결과로 실제 방문객들의 만족변화에 대해 탄력적인 반응을 보이는 것으로 분석되어졌다. 이를 통해 의사결정자들의 관리전략 구축시 수정된 IPA가 더 정확하고 신뢰성 높은 기초자료로 제공될 수 있을 것으로 기대된다.

• 대한한의학회지
• /
• 제43권1호
• /
• pp.136-153
• /
• 2022

Objectives: The aim of this study was to find out whether east asian herbal medicine (EAHM) treatment alone is effective in improving pregnancy-related indicators compared to conventional medicine in women with Diminished Ovarian Reserve (DOR). Methods: We searched eligible studies from PubMed, Cochrane Library, EMBASE, Chinese National Knowledge Infrastructure Database, CiNii, Korean Medical Database, Korean Studies Information Service System, Oriental Medicine Advanced Searching Integrated System, ScienceOn. GRADE pro was used to evaluate the current evidence of the study. Result: A total of 5 studies, 325 women with DOR were included. EAHM showed a significant effect on improvement of pregnancy rate (n=270, RR 2.13 [95% CI 1.44 to 3.15], Z=3.78, p=0.0002, I2=0%) and Anti-Mullerian Hormone (AMH) level (n=211, SMD 0.82 [95% CI 0.40 to 1.25], Z=3.80, p=0.0001) compared to conventional medicine. In ovulation rate (n=156, RR 0.86 [95% CI 0.70 to 1.06], Z=1.43, p=0.15, I2=0%), Antral Follicle Count (n=245, SMD 0.27 [95% CI -0.25 to 0.79], Z=1.01, p=0.31), and follicle stimulating hormone (n=245, SMD 0.29 [95% CI -0.13 to 0.70], Z=1.36, p=0.17) level, EAHM showed similar effects to conventional medicine. In this study, the most frequently used herbal medicines were Cuscutae Semen, Dipsaci Radix, and Angelicae Gigantis Radix. Conclusion: This meta-analysis showed that EAHM could improve pregnancy rates and AMH levels in women with DOR. However, more well-designed RCTs will have to be performed further in the future.

• ETRI Journal
• /
• 제30권2호
• /
• pp.216-226
• /
• 2008

This paper proposes a novel transport network architecture for the next generation network (NGN) based on the optical burst switching technology. The proposed architecture aims to provide efficient delivery of various types of network traffic by satisfying their quality-of-service constraints. To this end, we have developed a soft-state bandwidth reservation mechanism, which enables NGN transport nodes to dynamically reserve bandwidth needed for active data burst flows. The performance of the proposed mechanism is evaluated by means of numerical analysis and NS2 simulation. Our results show that the packet delay is kept within the constraint for each traffic flow and the burst loss rate is remarkably improved.

• 한국통신학회논문지
• /
• 제21권5호
• /
• pp.1200-1207
• /
• 1996

The paper presents and analyzes two efficient burst-level bandwidth reservation protocols for multi-hop ATM Local Area Networks. With the tell-and-wait (TNW) protocol and the tell-and-go (TNG) protocol[6], a negative acknowledgmen(NACK) message representing the bandwidth starvation on a switch on the source-destnation path can be always sent by a destination. We note that the protocols waste more bandwidth as the round-trip delay increases, since the switches on the path must reserve the bandwidth until the NACK will arrive. Based on this pitfall, the proposed protocols allow and ATM node, rather than a destination node to send a NACK. This allowance can save the needless bandwidth wastage. Using the thinned load approximation method, we show the proposed protocols have good performance and practical simplicity. Thus, the proposed protocols may be candidates for the ABR service in multi-hop ATM LANs and ATM WANs.

• International Journal of Human Ecology
• /
• 제14권2호
• /
• pp.79-91
• /
• 2013

The market for a payday advance, regarded as both a convenient and short term-loan for immediate financial help, has grown incredibly since the 1990's. Despite its popularity by borrowers and the possible benefits, it has received negative publicity. Some borrowers have been caught in a debt trap for a long-term period and at tripledigit interest rates. The objective of this study is to shed light on the borrowers' profiles and their demand for a payday advance. Based on the 2010 household level data from the U.S. Federal Reserve Board, this study finds that payday advance users are pronounced as seemingly risky people. Payday advance users tend to be college drop-outs, African Americans, and non-homeowners compared to non-payday advance users. They are more likely to overspend above their income and have a favorable attitude toward conspicuous spending than non-payday advance users. They tend not to shop at all nor perform even moderate shopping for credit before using a payday advance service as opposed to non-payday advance users.

• 산업경영시스템학회지
• /
• 제33권3호
• /
• pp.219-224
• /
• 2010

Depreciation accounting has as its main objective, the recovery of the original cost of plant investment less net salvage, over the estimated useful life of that plant. Accuracy of the whole life technique in meeting this objective depends entirely on the original estimates of service life and net salvages for an account. Where the whole life technique has been used and original estimates prove inaccurate, excessive or deficient accumulations in the depreciation reserve frequently occur. To overcome this, the remaining life technique is suggested to better match the challenges of accelerated technology and competition within the regulated environment. The flexibility of the remaining life technique will allow an even chance to provide a complete recovery of the original cost.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.274-275
• /
• 2015

에너지저장장치, 태양광 발전기, 전기자동차 등 직류 사용설비의 급증으로 인해 직류 배전 혹은 직류 마이크로그리드에 대한 관심이 증가하고 있다. 직류 배전은 전력변환을 최소화하여 효율이 높고 수변전 설비 공간이 절약되는 장점이 있다. 하지만 직류를 통해 계통에 연계된 부하와 설비들은 별도의 제어가 없으면 관성과 주파수-부하 반응을 제공할 수 없다. 따라서 직류 배전 투입이 늘어날수록 전력계통의 관성과 주파수-부하 반응이 감소하게 되어 계통 주파수 변동 발생 시 변동 속도와 크기가 증가하게 된다. 때문에 계통 운영자는 더 많은 주파수 조정 예비력을 확보하여야 한다. 본 논문에서는 동요방정식을 이용하여 직류 배전 투입에 따라 계통 관성과 주파수-부하반응이 줄어듦에 따라 변하는 필요 주파수 조정 예비력 량을 계산하는 방법을 제시하고 있으며 MATLAB을 이용하여 직류배전 투입 비율에 따른 필요 주파수 조정 예비력 량 변화를 모의하였다.

• 전자공학회논문지S
• /
• 제34S권8호
• /
• pp.1-9
• /
• 1997

Soft handoff provided in CDMA cellular system has much advantage such as better service quality, interference control and low call dropping probability. In this paepr, we propose an optimum resource reservationscheme for handoff calls in the CDMA cellular system to increase the soft handoff probability in handoff. In the proposed scheme, resources of each frquency channel are reserved for handoff according to the number of its neighbot cells serving the same frequency channel. A performance analysis shows that the soft handoff probability of the proposed scheme is higher than that of conventional scheme disregarding the condition of frquency assignment of neighbot cells, and that ever frequency channel served by neighbor cells should reserve more than one traffic channel for handoff to get good performance.