• 전기학회논문지
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• 제57권8호
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• pp.1318-1326
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• 2008

This paper proposes an alternative methodology for deciding an optimum deterministic reliability level (IRR; Installed Reserve Rate) by using probabilistic reliability criterion (LOLE; Loss of Load Expectation). Additionally, case studies using the proposed method induce the characteristics of relationship between the probabilistic reliability index (LOLE) and deterministic reliability index (IRR) for 2008 and 2010 years in Korea power system. The case study presents a possibility that an optimum IRR level in Korea can be assessed using the proposed method. Korea power system has been using the LOLE criterion to determine the adequacy of installed capacity (ICAP) requirement. The criterion in Korea is that the loss of load expectation shall not exceed the available capacity more than five day in ten years (=0.5[days/year]), The probabilistic reliability evaluation and production cost simulation program which is called PRASim is used in order to evaluate the relationship and optimum IRR in this paper.

• Journal of Biosystems Engineering
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• 제32권6호
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• pp.416-421
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• 2007

Physical damage to fruits and vegetables caused by shock degrades the value of product in the fresh market. In order to design a product/packaging system to protect the product, the G-factor to the product that causes shock damage needs to be determined. The shock fragility of organisms such as fruits with a concept correspondent to the G-factor of industrial products was calculated and we defined the allowable bio-shock fragility index as the value divided peak acceleration that was generated in safe drop height by standard acceleration of gravity. We did modeling for safe drop hight that would prevent fruits from damage by drop tests and tried to estimate the allowable bio-shock fragility index of pears and apples for optimum packaging design. The bio-shock fragility index of pears was in the range of $0.74{\sim}2.29\;G$, while apples had a slightly higher value than that of pears, of $0.51{\sim}2.98\;G$. This result shows accordance with the general fact that apples have a firmer structure and get less damage from the same impact. Based on this result, it is possible to create an optimum packaging design by providing a damage standard by impact.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.218-224
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• 1998

The coefficients of variation obtained from three typical vegetation indices of eight levels of multi-spatial resolution images in urban areas were employed to identify the optimum spatial resolution in terms of maintaining information quality. These multi-spatial resolution images were prepared by degrading 1 meter simulated, 16 meter ADEOS/AVNIR, and 30 meter Landsat-TM images. Normalized Difference Vegetation Index (NDVI), Perpendicular Vegetation Index (PVI) and Soil Adjusted Ratio Vegetation Index (SARVI) were applied to reduce data redundancy and compare the characteristics of multi-spatial resolution image of vegetation indices. The threshold point on the curve of the coefficient of variation was defined as the optimum resolution level for the analysis with multi-spatial resolution image sets. Also, the results from the image segmentation approach of region growing to extract man-made features were compared with these multi-spatial resolution image sets.

• 한국세라믹학회지
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• 제24권2호
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• pp.170-178
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• 1987

Changes of the properties of PECVD-SiN film with the variation of deposition process parameters were investigated and optimum process parameters were determined. The refractive index of the film increased with increasing substrate temperature and pressure, and decreasing rf-power, NH3/SiH4 gas ratio and total gas flow. BHF etch rate and deposition rate show a decreasing tendency with increasing refractive index. The step coverage of the film was not affected much by deposition rate and pressure, but improved apparently with increasing rf-power and NH3/SiH4 gas ratio. Also the optimum process parameters were determined by considering the characteristic properties as well as thickness uniformity of films. The refractive index of the film deposited under this condition was 2.06.

• 수산해양기술연구
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• 제30권2호
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• pp.86-96
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• 1994

In order to estimate the optimum harvesting mesh size of multispecies, the 24 species of catching data which were taken by fishing trial of trawl gear in Korean Southern Coast and East China Sea during 1991-1993 year were grouped and divided by the Cluster analysis method, considering first maturity length and body width, body height, body girth based on the first maturity length. With the same method, the above groups were subdivided by the potential escape such as possible escape index, range factor and selection factor. In case of the species devoid of selection parameters, these species were first subdivided by the use of possible escape index and length range factor. Next, the optimum harvesting mesh size of multispecies was properly classified according to the optimal mesh size of a fish estimated by first maturity length against selection factor. The results obtained are summarized as follows: 1. Each optimum harvesting mesh size of Psenopsis anomala, Priacanthus macra-canthus, Trachurus japonicus, Argyrosomus argentatus was 71.1-79.5mm, and Saurida undosquamis was 65.5mm. 2. Each optimum harvesting mesh size of Scomber japonicus, Pseudosciaena crosea, Pseudosciaena Polyactis, Sebastes thompsoni, Doderleinia berycoides was 78.5-85.6mm, and Bembras japonicus, Sphyraena pinguis was 48.4-51.3mm. 3. Each optimum harvesting mesh size of Zeus faber, Pampus argenteus, Zenopsis nebulosan was 118.4-124.1mm, and Caranx equula was 91.4mm, and Thamnaconus modestus was 131.2mm, and Pagrus major was 149.4mm. 4. Each optimum harvesting mesh size of Upeneus bensasi, Callanthias japonicus, Sardinops melanosticata, Konosirus punctatus was 36.8-42.8mm, and Acropoma japonicum was 21.2mm, and Apogon lineatus was 26.3mm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.103-104
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• 2008

This paper proposes an alternative methodology for deciding an optimum deterministic reliability level (IRR; Installed Reserve Rate) by using probabilistic reliability criterion (LOLE; Loss of Load Expectation). Additionally, case studies using the proposed method induce the characteristics of relationship between the probabilistic reliability index (LOLE) and deterministic reliability index (IRR) for 2008 year in Korea power system. The case study presents a possibility that an optimum IRR level in Korea can be assessed using the proposed method. Korea power system has been using the LOLE criterion to determine the adequacy of installed capacity (ICAP) requirement. The criterion in Korea is that the loss of load expectation shall not exceed the available capacity more than five day in ten years (=0.5[days/year]). The probabilistic reliability evaluation and production cost simulation program which is called PRASim is used in order to evaluate the relationship and optimum IRR in this paper.

• 한국기계가공학회지
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• 제8권4호
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• pp.69-75
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• 2009

Recently developed automotive components are getting lighter providing a higher fuel efficiency and performance. Following the current trend, this study proposes a structural optimization method for the lower control arm installed at the front side of a Vehicle. Lightweight design of lower control arm can be achieved through design and material technology. In this research, the shape of lower control arm was determined by applying the optimization technology and aluminum was selected as a steel-substitute material. Strength performance is the most important design requirement in the structural design of a control arm. This study considers the static strength in the optimization process. For the optimum design, the durability analysis is performed to predict its fatigue life. In this study, the kriging interpolation method is adopted to obtain the minimum weight satisfying the strength constraint. Optimum designs are obtained by the in-house program, EXCEL-Kriging. Also, based on the optimum model obtained for the static strength, the optimization of Index of Fatigue Durability is carried out to get th optimum fatigue performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.62-65
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• 1989

Optimizing transient response for both tracking reference signals and disturbance rejection is determined by the poles and zeros of the transfer function. Thus, optimal pole assignment and how should weighting matrix for the performance index be chosen is very important to achieve optimum transient response. This paper focus its attention on the choosing and analysis of weighting matrix for optimum pole assignment. Optimum pole assignment is defined for linear time-invariant continuous systems.

• 한국해양공학회지
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• 제23권6호
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• pp.131-135
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• 2009

We present an optimum design method for a rectangular reinforced concrete beam using Genetic Algorithms. The optimum design procedure in this paper employs 2 design cases: i) all of the design variables (b, d, As) of the rectangular reinforced concrete section are used pseudo-continuously, ii) one is pseudo-continuous for the concrete cross section (b, d) and the other is discrete, using an index for the steel area (As). The optimum design in this paper uses Chakrabarty's model. In this paper, the Genetic Algorithms use the method of Elitism and penalty parameters to improve the fitness in the reproduction process, which leads to very practical designs. The optimum design of the steel area in the examples uses ASTM standard reinforcing bars (#3~#11, #14, #18).

• 한국통신학회논문지
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• 제19권6호
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• pp.1064-1074
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• 1994

본 논문에서는 주파수 선택성 페이팅 채널의 일종인 two-ray 패이딩 채널에서 TCM(trellis coded modulation)을 CPM(continuous phase modulation) 신호에 적용하였을 때 최적의 TCM을 찾고, 이때의 성능 개선치를 평가하였다. CPM 신호로는 비교적 전력 효율 및 대역 효율이 좋은 IREC, 3RC 및 GMSK를 선택히여 변조 지수를 0.1에서 0.6으로 변화시켜 각 변조 지수에서 성능을 평가하였다. 그리고 TCM을 구성하는 부호기의 구속 길이는 2와 3으로 하였다. 성능평가 결과 구속 길이가 3인 최적의 TCM은 변조지수가 0.5일때 페이딩 채널에서 부호화 되지 않은 경우와 비교하여 1 REC에서 약 2.0dB의 전력이득이 있고 3RC에서 약 2.1dB의 전력 이득이 각각 있었다. 따라서 본 논문에서 제시한 최적의 TCM을 디지털 이동 통신에 적용할 경우 상당한 선로 품질의 향상을 이룰 수 있으리라고 기대된다.