• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2134-2135
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• 2006

전력거래소는 발전경쟁시장(CBP; Cost-Based Pool) 장기화에 따른 운영상의 효율성을 개선하고 기 개발된 시장운영시스템(MOS; Market Operation System)을 활용하여 급전체계를 개선하기 위해 준비중이다. 현행 급전체계에서는 거래 전일에 수행한 수요예측을 바탕으로 1시간 단위운영발전계획을 전일에 수립하고 EMS(Energy Management System)를 이용하여 발전기에 대한 경제부하배분(ED; Economic Dispatch)을 시행하고 있지만, 현 EMS는 시장체제 환경 전에 도입된 설비로 시장환경에 대한 고려가 되어 있지 않고 계통운영 보조서비스의 실시간 반영이 어려운 점이 있다. 전력거래소는 실시간 급전 운영을 위해 기존 EMS에 MOS를 연계하여 MOS의 5분 단위 수요예측량을 기반으로 송전망 제약과 예비력 요구량 등을 고려한 발전기별 경제부하 배분량 및 예비력 배분량을 결정하고, 추가적으로 EMS에서 수요예측 오차 및 주파수 보정량을 실시간으로 계산하여 발전기별로 배분하도록 함으로써, 1일 전 시행하던 급전계획을 취득 자료를 기반으로 5분 단위로 실시간 계산할 수 있도록 급전 체계를 개선할 계획이다. 이를 통해 실시간으로 에너지와 예비력을 동시에 최적화함으로 전력시장 및 전력계통 운영을 한층 선진화 할 수 있는 계기를 마련하였으며 또한 저비용 발전기 사용을 극대화함으로 발전비용의 절감에도 기여하는 효과를 기대할 수 있다. MOS-EMS간 자료연계에는 ICCP(Inter-Control Communication Protocol)와 FTP 프로토콜을 사용하였고, 수차례 모의운영을 통하여 데이터베이스 및 현장 취득 자료의 정확도(accuracy)가 양 시스템 간 연계 및 전력 계통의 안정적 운영에 매우 중요한 요소로 나타났다. 전력거래소는 장기적으로 CIM(Common Information Model)기반의 표준 전력계통 데이터베이스를 구축하고 시스템 간 자료 연계를 위해 XML을 활용하여 시스템 간 상호 운영성(Interoperability)과 자료 연계의 안정성을 높일 계획이다. 본 논문은 MOS-EMS 연계에 따른 시스템 간 자료의 흐름 및 처리에 대해 주로 설명하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.732-739
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• 2016

In Korea, the summer is hot and humid, and much electricity is consumed for air conditioning. Thus, the simultaneous usage of an indirect evaporative cooler and a common air conditioner could reduce the sensible heat and save electricity. This study developed a U-type cross-counter flow indirect evaporative cooler (IEC) made of plastic and paper. The efficiencies were compared with those of a cross-flow IEC. The specimen was $500mm{\times}500mm{\times}1000mm$. the results show that the indirect evaporation efficiencies of the cross-counter flow sample were 6-21% higher than those of the cross-flow sample. The pressure drops of the cross-counter sample were 51-66% higher. Thermal analysis based on the -NTU method predicted the experimental data within 10%. The electrical energy saved by the use of the cross-counter flow IEC was larger than that of the counter flow IEC, and the difference increases with the velocity. However, the the cross-counter IEC is two times larger than the cross-flow IEC, which may increase the material cost and water usage.

• Journal of Korean Society of Transportation
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• v.18 no.3
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• pp.77-86
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• 2000

The shortest path problem is one of the mathematical Programming models that can be conveniently solved through the use of networks. The common shortest Path Problem is to minimize a single objective function such as distance, time or cost between two specified nodes in a transportation network. The sing1e objective model is not sufficient to reflect any Practical Problem with multiple conflicting objectives in the real world applications. In this paper, we consider the shortest Path Problem under multiple objective environment. Wile the shortest path problem with single objective is solvable in Polynomial time, the shortest Path Problem with multiple objectives is NP-complete. A genetic a1gorithm approach is developed to deal with this Problem. The results of the experimental investigation of the effectiveness of the algorithm are also Presented.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.4
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• pp.211-221
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• 2017

Ellipsodially referenced survey (ERS) is considered as one of the challenging issues in the hydrographic surveys due to the fact that the bathymetric data collected by this technique can be readily transformed either to the geodetic or the chart datum by application of some geoscientific models. Global Navigation Satellite Systems (GNSS) is a preferred technique to determine the ellipsoidal height of a vessel reference point (RP) because it provides cost-effective and unprecedentedly accurate positioning solutions. Especially, the GNSS-derived heights include heave and dynamic draft of a vessel, so as for the reduced bathymetric solutions to be potentially free from these corrections. Although over the last few decades, differential GNSS (DGNSS) has been widely adopted in the bathymetric surveys, it only provides limited accuracy of the vertical component. This technical barrier can be effectively overcome by adopting the so-called GNSS carrier phase (CPH) based techniques, enhancing accuracy of the height solution up to few centimeters. From the positioning algorithm standpoint, the CPH-based techniques are categorized under absolute and relative positioning in post-processing mode; the former is precise point positioning (PPP) correcting errors by the global or regional models, the latter is post-processed kinematic positioning (PPK) that uses the differencing technique to common error sources between two receivers. This study has focused on assessment of achievable accuracy of the ellipsoidal heights obtained from these CPH-based techniques with a view to their applications to hydrographic surveys where project area is, especially, few tens to hundreds kilometers away from the shore. Some field trials have been designed and performed so as to collect GNSS observables on static and kinematic mode. In this paper, details of these tests and processed results are presented and discussed.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.493-509
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• 1998

Osteoarthritis(degenerative joint disease), the most common arthropathy affecting the aged people, is characterized by degeneration of articular cartilage with proliferation and remodeling of subchondral bone. Osteoarthritis of the knee, which probably has greater social cost and more associated disability than osteoarthritis of any other joint, prevalence is known to increase with age, and females have higher rates than males; radiographic abnormalities are present in more than 30% of persons more than 65 years old, with approximately 40% of these persons symptomatic. Though the etiology of osteoarthritis is not entirely understood, much information is available regarding risk factors for the development of knee osteoarthritis that permit some reasonable guideline for preventive strategies. Traumatic damage or occupational or recreational overuse of knee joint may result in osteoarthritis, and obesity also is related to osteoarthritis of the knee. A variety of other possible risk factors for the development of knee osteoarthritis have been proposed, including increased bone mass, smoking, diseases such as diabetes or elevated serum uric acid, and some metabolic factors, but the contribustions of these and other factors such as smoking or race and diseases such as diabetes are as yet undetermined. The usual clinical manifestations include pain, stiffnesss, crepitus and loss of function. In oriental medicine, osteoarthritis of the knee is very similar to diseases such as Bijung(痺症), Haksulpung(鶴膝風), Youkjeolpung(歷節風) in symptoms. The diseases such as Bijung(痺症), Haksuipung(鶴膝風), Youkjeolpung(歷節風) is related to the of function liver(肝) and kidney(腎) and risk factors are regarded as Pung(風), Han(寒), sub(濕). The diagnosis of osteoarthritis of the knee has often been based on radiographic appearance and clinical manifestations. The acupuncture therapy of osteoarthritis of the knee has often been based on Stomach meridian(ST), Spleen meridian(SP), Kidney meridian(KI), Liver meridian(LR).

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8619-8623
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• 2016

Background: Breast cancer is a common disorder in women, constituting one of the main causes of death all over the world. The purpose of this study was to determine the diagnostic value of the breast tissue diseases by the help of thermography. Materials and Methods: In this paper, we applied non-contact infrared camera, INFREC R500 for evaluating the capabilities of thermography. The study was conducted on 60 patients suspected of breast disease, who were referred to Imam Khomeini Imaging Center. Information obtained from the questionnaires and clinical examinations along with the obtained diagnostic results from ultrasound images, biopsies and thermography, were analyzed. The results indicated that the use of thermography as well as the asymmetry technique is useful in identifying hypoechoic as well as cystic masses. It should be noted that the patient should not suffer from breast discharge. Results: The accuracy of asymmetry technique identification is respectively 91/89% and 92/30%. Also the accuracy of the exact location of identification is on the 61/53% and 75%. The approach also proved effective in identifying heterogeneous lesions, fibroadenomas, and intraductal masses, but not ISO-echoes and calcified masses. Conclusions: According to the results of the investigation, thermography may be useful in the initial screening and supplementation of diagnostic procedures due to its safety (its non-radiation properties), low cost and the good recognition of breast tissue disease.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.2141-2146
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• 2013

Cervical cancer is the third most common form of cancer that strikes Malaysian women. The National Cancer Registry in 2006 and 2007 reported that the age standardized incidence (ASR) of cervical cancer was 12.2 and 7.8 per 100,000 women, respectively. The cumulative risk of developing cervical cancer for a Malaysian woman is 0.9 for 74 years. Among all ethnic groups, the Chinese experienced the highest incidence rate in 2006, followed by Indians and Malays. The percentage cervical cancer detected at stage I and II was 55% (stage I: 21.0%, stage II: 34.0%, stage III: 26.0% and stage IV: 19.0%). Data from Ministry of Health Malaysia (2006) showed a 58.9% estimated coverage of pap smear screening conducted among those aged 30-49 years. Only a small percentage of women aged 50-59 and 50-65 years old were screened, 14% and 13.8% coverage, respectively. Incidence of cervical cancer was highest (71.6%) among those in the 60-65 age group (MOH, 2003). Currently, there is no organized population-based screening program available for the whole of Malaysia. A pilot project was initiated in 2006, to move from opportunistic cervical screening of women who attend antenatal and postnatal visits to a population based approach to be able to monitor the women through the screening pathway and encourage women at highest risk to be screened. The project was modelled on the screening program in Australia with some modifications to suit the Malaysian setting. Substantial challenges have been identified, particularly in relation to information systems for call and recall of women, as well as laboratory reporting and quality assurance. A cost-effective locally-specific approach to organized screening, that will provide the infrastructure for increasing participation in the cervical cancer screening program, is urgently required.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.31-39
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• 2007

To perform on-line cyber education, it is indispensable to delivery contents file to participant users. When users' requests occur simultaneously in a shot period, server falls into overload phase. A common to avoid overload is a software solution based on P2P, which does no cost any additional expense. But, in this solution, it yields many problems such as service delay and system failure because of peer self-control. In this paper we propose an efficient load balancing policy based on P2P system. which is the contents delivery system for cyber education system using idle computing power in the proposed solution, we present server selection scheme called P2P-Pattern method, which results in minimum service delay. we can see that our scheme outperforms previous scheme.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.113-123
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• 2020

Obstructive sleep apnea (OSA) among sleep disorders is one of relatively common diseases. Patients can be checked for the disease through sleep polysomnography. However, as far as he diagnosis of OSA using polysomnography (PSG) is concerned, many practical problems such as an increasing number of patients, expensive testing cost, discomfort during examination, and the limited number of people for testing have been pointed out. Accordingly, for the purpose of substituting PSG researchers have been actively conducting studies on OSA diagnosis based on machine learning using bio signals. In this regard, we review a rich body of existing OSA diagnosis studies applying machine learning techniques based on bio-signal data. As a result, this paper presents a novel taxonomy of the reviewed studies and provides their comprehensive comparative analysis results. Also, we reveal various limitations of the studies using the bio signals and suggest several improvements about utilization of the used machine learning methods. Finally, this paper presents future research topics related to the application of machine learning techniques using bio signals.

• International Journal of Reliability and Applications
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• v.7 no.1
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• pp.27-39
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• 2006

Many real world cases in material failure analysis do not follow perfectly the normal distribution. Forcing of the normality assumption may lead to inaccurate predictions and poor product quality. We examine the failure process of the internal bond (IB or tensile strength) of medium density fiberboard (MDF). We propose a forced censoring technique that closer fits the lower tails of strength distributions and better estimates extremely smaller percentiles, which may be valuable to continuous quality improvement initiatives. Further analyses are performed to build an accelerated common-shaped Weibull model for different product types using the $JMP^{(R)}$ Survival and Reliability platform. In this paper, a forced censoring technique is implemented for the first time as a software module, using $JMP^{(R)}$ Scripting Language (JSL) to expedite data processing, which is crucial for real-time manufacturing settings. Also, we use JSL to automate the task of fitting an accelerated Weibull model and testing model homogeneity in the shape parameter. Finally, a package script is written to readily provide field engineers customized reporting for model visualization, parameter estimation, and percentile forecasting. Our approach may be more accurate for product conformance evaluation, plus help reduce the cost of destructive testing and data management due to reduced frequency of testing. It may also be valuable for preventing field failure and improved product safety even when destructive testing is not reduced by yielding higher precision intervals at the same confidence level.