• 한국정보과학회논문지:정보통신
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• 제31권5호
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• pp.519-531
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• 2004

무선 애드혹 통신망은 고정된 기간망 없이 이동 기기들이 모여서 형성하는 임시 무선 시스템이다. 무선 애드혹 통신망에서는 이동 기기들이 모여서 통신망을 형성하므로 개개의 이동 기기의 수명이 통신망 자체의 수명을 결정짓는 중요한 요소가 된다. 망의 구조에 따라서 어떠한 경우는 단지 하나의 이동 기기가 자신의 배터리를 모두 소모하고 동작을 멈추었을 뿐인데, 이것이 통신망의 분할(partition)을 가져올 수도 있다. 이처럼 이동 기기의 수명은 각 이동 기기가 가지고 있는 배터리에 의존하므로 될 수 있는 한 소모하는 에너지량을 줄여 모든 이동 기기들이 골고루 오래 살수 있도록 하는 것이 전체 통신망의 수명을 늘릴 수 있는 방안이 된다. 본 연구에서는 모든 이동 기기들이 오랫동안 함께 살 수 있도록 최적의 경로를 선택하여 통신을 하도록 하는 전력 인식 동적 소스 라우팅(Power-Aware Dynamic Source Routing: PADSR) 프로토콜을 제안한다. PADSR에서는 송신 기기가 패킷(packet) 전송을 위한 경로를 선택할 때 어떤 특정 이동 기기의가 에너지를 많이 소모하지 않도록 하기 위하여 경로 선택 시에 경로에 포함되어 있는 이동 기기들의 남아있는 배터리량과 패킷을 전달하는데 소모하게 되는 송신 에너지량을 고려한다. 따라서 PADSR을 사용하게 되면 통신망의 수명이 연장된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1405-1405
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• 2011

Sudden earthquake is changing national energy stratagem for future energy resource. In case Germany, current nuke power station will be shut down with several decades. Newly constructed build in Japan must have photovoltaic system as a obligations.. As a long-term sustainable energy one, PV should give confidence to customers up to more than 20 years. Today, IEC 61215 and IEC 61646 standards are representative one for ensuring performance and safety of PV module. But it is still needed to develop more realistic test method. For example, if we think about extreme condition like desert and North Pole, the temperature condition describe in test standards can have little effect on life time expectation of PV module. Installation speed of PV system is very high, but establishing test standards are very complex and not easy. So in this paper, I tried to open the long-term test method for PV module to ensure 25 year's old life time. It is just starting point of PV related long-term test methods. The specific and technical explanation will be shown in the following paper in detail.

• 한국유체기계학회 논문집
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• 제16권5호
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• pp.18-23
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• 2013

Thermal aging test is performed to qualify the life time of equipment in thermally aged condition. Due to long life time more than 10 years like as in power plant, the equipment is subjected to the accelerated thermal aging condition which is able to shorten the long aging test period by increasing aging temperature. Normally, conservatism of thermal aging test causes to impose unbalanced and excessive thermal load on components of the equipment, and deformation and damage problems of the components. Additionally, temperature rise of each component through heat generation of the electric equipment leads to long-term problem of the test period. Multi-phase accelerating aging test is to perform thermal aging test in multiple aging conditions after dividing into groups with various components of equipment. The groups might be classified considering various factors such as activation energy, temperature rise, glass transition temperature and melting temperature. In this study, we verify that the multi-phase accelerating aging test method can reduce and equalize the thermal over load of the components and shorten aging test time.

• 대기
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• 제19권3호
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• pp.243-253
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• 2009

In other to interpret the long-term variations of sunshine duration, cloud lifetime, and precipitation intensity observed in and around Seoul and Busan for the period from 1986 to 2005, aerosol indirect effect was employed and applied. For the identification of long-term trend of aerosol concentration, observed visibility and AOT of AERONET sunphotometer data were also used over the same regions. The result showed that the time series of visibility was decreased and those of AOT increased, especially trends were remarkable in 2000s. In both regions, occurrence frequencies of observed cloudiness (cloud amount ${\leq}6/10$) and strong precipitation (rain rate > $0.5mmhour^{-1}$) have been steadily increased while those of cloudiness (cloud amount > 7/10) and weak precipitation (rain rate ${\leq}0.2mmhour^{-1}$) decreased. These results are corresponding to the trend of both visibility and AERONET data, implying the aerosol indirect effect that makes size of cloud droplet reduce, cloud life-time longer and precipitation efficiency decreased. Our findings demonstrate that, although these phenomena are not highly significant, weather and climate system over Korean urban area have been changed toward longer lifetime of small cloudiness and increasing precipitation intensity as a result of increased aerosol indirect effect.

• KIEAE Journal
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• 제3권3호
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• pp.67-74
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• 2003

The repair and maintenance planning is the principal transaction to prevent from the degradation of apartment buildings to prolong their lives. Various building components as part of living area should be maintained properly and timely before critical defects are realized, then the building life might be extended until the limit of its usability. In other words, various building components such as utilities, finishes and structural members are needed to be repaired and replaced in different time interval after completion. To do this systematically, a maintenance management system for Long-Range Planning (LRP) needs developing. The LRP should be figured out based on the forecast of repairing and replacing cycle of building components according to work trades. And the precise forecast of repairing and replacing time of the components helps to enhance the usability of the developed system. The purpose of this paper is to suggest a system with which apartment building managers carry out the tasks of periodical check, diagnosis and replacement of building components based on the maintenance calendar. By using the system, they can easily forecast repairing and replacing time of the components with the consideration of life cycle of building materials and build the LRP.

• Communications for Statistical Applications and Methods
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• 제28권5호
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• pp.521-536
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• 2021

As life expectancies increase continuously over the world, the accuracy of forecasting mortality is more and more important to maintain social systems in the aging era. Currently, the most popular model used is the Lee-Carter model but various studies have been conducted to improve this model with one of them being 6-parametric factor model (6-PFM) which is introduced in this paper. To this new model, long short-term memory (LSTM) and regularized LSTM are applied in addition to vector autoregression (VAR), which is a traditional time-series method. Forecasting accuracies of several models, including the LC model, 4-PFM, 5-PFM, and 3 6-PFM's, are compared by using the U.S. and Korea life-tables. The results show that 6-PFM forecasts better than the other models (LC model, 4-PFM, and 5-PFM). Among the three 6-PFMs studied, regularized LSTM performs better than the other two methods for most of the tests.

• 한국주거학회논문집
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• 제16권5호
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• pp.67-74
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• 2005

The performance of building should be deteriorated with time while the building would maintain and manage the function and performance to get a living condition. For the efficient maintenance of the building, the repair cycle would be provided and applied during the service-life time. The service-life time of the building components would be needed to determine the repair time and the repair scope. The service-life time of the building components would be calculated with the 1st repair time and the recovery rate of the performance, considering the recovery rate after repaired. In this paper, the 1st repair time would be estimated with the normal probability distribution, choice probability and 3rd quadratic function. The recovery rate of the building components assumes various level according to the research target and utility area. The results of this study are as follows ; first, most of the components of the building work would range about 30 years in the service-life time and the components of the mechanical works range from 28 years to 37 years, those of the electrical works would be about 31 years.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.652-655
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• 2003

The human being receives a new information from outside and the information shows gradual oblivion with time. But it remains in memory and isn't forgotten for a long time if the information is read several times over. For example, we assume that we memorize a telephone number when we listen and never remind we may forget it soon, but we commit to memory long time by repeating. If the human being received new information with strong stimulus, it could remain in memory without recalling repeatedly. The moments of almost losing one's life in on accident or getting a stroke of luck are rarely forgiven. The human being can keep memory for a long time in spite of the limit of memory for the mechanism mentioned above. In this paper, we will make a model explaining that mechanism using a neural network Adaptive Resonance Theory.

• 가정과삶의질연구
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• 제21권4호
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• pp.1-10
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• 2003

This paper compares the time perspective between Korean and American college students and examines the difference of it according to gender and social status of them. The subject of this study were 385 Korean students and 385 American counterparts. The data were collected by survey with questionnaires and analyzed by SPSS program for the frequency, percentile, mean, standard deviation, t-test, one-way ANOVA and Duncan test. The results indicate that American students have more long-term personal direction than Korean counterparts and the effects of gender and social status are different in Korea and America. Korean students showed no difference according to these two variables but female America students indicate more long-term personal direction than male students and the time perspectives were different according to social status in America.

• Asian-Australasian Journal of Animal Sciences
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• 제32권2호
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• pp.282-289
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• 2019

Objective: This study aimed to elucidate whether innovative sous vide treatment has a significant influence on the beef semitendinosus muscle as compared to common sous vide treatment and traditional cooking. Methods: The innovative sous vide treatments were cooked at $45^{\circ}C$ and $65^{\circ}C$ for 6 h (SV45-65), common sous vide treatment at $45^{\circ}C$ and $65^{\circ}C$ for 3 h (SV45 and SV65) and traditional cooking at $75^{\circ}C$ for 30 min (CON75). Water loss and cooking loss, as well as the physical properties (color and shear force) and chemical properties (protein and collagen solubility) of the treated meat, were investigated. Results: The results obtained indicated that the innovative sous vide with double thermal treatment (SV45-65) and cooked with air presence (CON75) resulted to lower $a^*$ and higher $b^*$ values, respectively. The water loss and cooking loss increased when temperature increased from $45^{\circ}C$ to $65^{\circ}C$, and lower water loss was recorded in SV45 and CON75. These samples presented higher water content and revealed strong correlation to protein solubility. Warner-Bratzler shear force (SF) analysis showed the marked interaction between cooking temperature and time. Sample cooked at a high temperature (CON75) and a long period (SV45-65) showed a significantly lower value of SF than sample SV65 (p<0.05). Interestingly, there was no difference in SF values between SV45-65 and CON75. Conclusion: The innovative sous vide treatment with double thermal effect appears an attractive cooking method as compared to common sous vide and traditional cooking method, as it has a potential for improving tenderness values of cooked beef semitendinosus muscle.