• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2490-2506
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• 2022

In Mobile Edge Computing (MEC), attackers can speculate and mine sensitive user information by eavesdropping wireless channel status and offloading usage pattern, leading to user privacy leakage. To solve this problem, this paper proposes a Privacy-preserving and Energy-efficient Offloading Algorithm (PEOA) based on Lyapunov optimization. In this method, a continuous Markov process offloading model with a buffer queue strategy is built first. Then the amount of privacy of offloading usage pattern in wireless channel is defined. Finally, by introducing the Lyapunov optimization, the problem of minimum average energy consumption in continuous state transition process with privacy constraints in the infinite time domain is transformed into the minimum value problem of each timeslot, which reduces the complexity of algorithms and helps obtain the optimal solution while maintaining low energy consumption. The experimental results show that, compared with other methods, PEOA can maintain the amount of privacy accumulation in the system near zero, while sustaining low average energy consumption costs. This makes it difficult for attackers to infer sensitive user information through offloading usage patterns, thus effectively protecting user privacy and safety.

• 한국식생활문화학회지
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• 제22권1호
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• pp.10-21
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• 2007

The purpose of this study was to investigate the housewives’ consumption pattern and preference of the Korean rice cake asa substitute for meal. The rate of housewives who had eaten rice cake as a substitute for meal were 75.30% and those who had not were 20.83%. Usually 62.03% of them ate rice cake for breakfast, and 34.21% did them within one time per a week. Reasons for eating rice cake for meal were investigated on ‘easy to eat(54.51%)’, ‘good taste (24.44%)’ and ‘healthy food(14.29%)’. The older housewives wanted healthy rice cake for meal and ate with tea and Kimchi(Dongchimi). The younger ones ate rice cake for meal with tea and milk. Thawing methods of frozen rice cake for meal were different between the older and the younger, respectively, steaming and using microwave. Kinds of rice cake as a substitute meal were Injeolmi(50.75%), Backsulgi(49.62%), Chaltteok (47.74%) and Yaksik(46.44).

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.127-132
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• 2011

Worldwide, the building energy simulation becomes inevitable step for predicting the energy consumption in building. In simulation process, the expertise is required for the accurate analysis results. In Korea, however, most of user use the inconsistent data with Korea circumstance. In this step, we need to construct the standard input data matched building in Korea. In this study, electricity consumption of apartments in Daejeon is analyzed. The yearly data of a apartment complexes of 2009 are analyzed as monthly, daily(week and weekend), timely, and completion year. With this result, we are able to predict the demand pattern of electricity in a house and make the schedule by demand pattern. The results of this study are followed. The averaged amount of electricity consumption in winter is higher than summer because of the high capacity of heating equipment. All of the house has electric base load from 0.26kWh to 0.5kWh. The average of the electricity consumption of month is shown as 326.7kWh. A week is seperated as 4 part such as week, weekend, Saturday and Sunday. During week, the average of timely electricity consumption is shown as 0.442kWh. The Saturday consumption is 0.453kWh. The Sunday is 0.461kWh.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권6호
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• pp.1546-1564
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• 2012

Pattern-based query processing has not attracted much attention in wireless sensor network though its counterpart has been studied extensively in data stream. The methods used for data stream usually consume large memory and much energy. This conflicts with the fact that wireless sensor networks are heavily constrained by their hardware resources. In this paper, we use piece wise representation to represent sensor nodes' collected data to save sensor nodes' memory and to reduce the energy consumption for query. After getting data stream's and patterns' approximated line segments, we record each line's slope. We do similar matching on slope sequences. We compute the dynamic time warping distance between slope sequences. If the distance is less than user defined threshold, we say that the subsequence is similar to the pattern. We do experiments on STM32W108 processor to evaluate our strategy's performance compared with naive method. The results show that our strategy's matching precision is less than that of naive method, but our method's energy consumption is much better than that of naive approach. The strategy proposed in this paper can be used in wireless sensor network to process pattern-based queries.

• 한국지열·수열에너지학회논문집
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• 제14권2호
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• pp.1-7
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• 2018

The purpose of this study was to analyze the energy consumption of Elementary, Middle and High Schools in Daejeon Metropolitan City. The main results are as follow: 1) Annual energy consumption per class was 12,825 (kWh/class) at elementary schools, 15,780 (kWh/class) at middle schools, and 29,447 (kWh/class) at high schools, 2) Generally the smaller the size of the school, the higher the energy consumption per class. However according to the HVAC system there was no consistent pattern of energy consumption per class. 3) According to Box and Whisker's Chart, distribution of energy consumption of elementary and middle schools' had small range. However, the range of high schools increased. 4) Energy consumption in winter season was larger than that of summer season in schools.

• 대한전기학회논문지:전력기술부문A
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• 제52권2호
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• pp.79-89
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• 2003

A research about finding a new electricity load model that is sensitive to the price of electricity is conducted. This new model i5 polynomial type price sensitive electricity consumption model, while former electricity consumption models have exponential terms or statistic terms. The pattern of electricity consumption of each electricity using devices were identified first, then the proportion of the devices at buses or nodes are investigated, finally weighted sum of electricity consumption and the proportion makes the load model or consumption model of electricity at one bus or node. This new model is easy to use in the simulations or calculations of the electricity consumption, because the arithmetic of functions with polynomial terms are easy compared to the functions with transcendental terms.

• 설비공학논문집
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• 제17권1호
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• pp.82-87
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• 2005

The purpose of this study is to suggest the characteristics and actual state of energy consumption by the analysis of energy consumption data in an office building. This study examines and analyzes daily and monthly energy consumption of an office building located in Seoul, Korea regarding type of load and business classification within a building. The results are as follows. 1) Energy consumption of office building for each type of load show similar consumption patterns, regardless of seasons such as cooling period and heating period. 2) Out of all annual energy consumption, consumption for lighting took about $43\;\%,$ general electric Power about $23\;\%,$ emergency power $25\;\%,$ computer center $5\;\%$ and cooling power $4\;\%,$ showing that the consumption for lighting was highest, and the percentage of energy consumption for cooling power for operation of cooling facilities took the lowest percentage. 3) Annual gas consumption used for heating and hot water supply were $38,\;36\;\%$ for officetel and office respectively, and $26\;\%$ for arcade. 4) Electricity consumptions used for cooling power for each use of building, office and officetel recorded in July and August of cooling seasons. Even though it shows different patterns for each month, energy consumption showed unique pattern throughout the cooling seasons.

• Journal of Nutrition and Health
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• 제40권5호
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• pp.451-462
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• 2007

본 연구는 한국 성인의 아침식사유형과 주식유형에 따른 식사의 질과 건강상태를 비교분석하기 위하여 수행되었다. 연구 자료는 2001년도 국민건강영양조사자료 중 $30{\sim}49$세 남자 1,641명, 여자 1,765명의 자료를 이용하였다. 대상자들의 아침 섭취여부 및 아침식사의 유형에 따라 사회인구학적 특성, 영양소 및 식품섭취, 대사증후군 관련 건강상태지표를 분석하였다. 아침식사의 유형은 섭취하는 주식에 따라 'RICE' (밥식), 'BREAD' (빵식), 'NOODLE' (면식), 'OTHERS' (기타식)로 분류하였고 그 밖의 혼합유형은 분석에서 제외하였다. 분석된 주요 결과는 다음과 같다. 아침식사를 거를 때, 영양소의 충분한 섭취라는 측면에서 하루 식사의 질이 아침식사를 섭취하는 것에 미치지 못하는 것으로 나타났다. 그러나 아침식사를 거를 때와 섭취할 때 건강지표상의 의미 있는 차이는 찾을 수 없었으며, 아침식사를 섭취하는 경우 주식을 중심으로 섭취하는 식사의 구성에 따라 몇 가지 의미 있는 차이를 관찰하였다. 첫째, 아침식사유형이 빵식인 대상자들의 월 가구소득이 높았으며, 특히 여자대상자에서는 아침식사의 유형이 면식인 대상자의 평균 월 가구소득이 가장 낮았다. 둘째, 아침식사유형 간 만성질환 유병율의 분포에는 차이가 없었으나, 각 건강지표의 평균수준에 차이가 있었다. 남자 대상자에서는 아침식사유형이 빵식일 때 혈중 총 콜레스테롤이 높은 수준을 나타내었다. 여자대상자에서는 이러한 특징이 관찰되지 않았고 아침식사유형이 면식인 대상자의 HDL수준이 낮고 공복 시 혈당이 높았으며 통계적으로 의미 있는 차이를 나타내었다. 셋째, 남녀대상자 모두에서 빵식인 아침식사는 지방 에너지의 비중이 높았으며 미량 영양소의 밀도는 낮은 수준이었다. 하루 중 다른 끼니의 섭취를 통해 부족한 미량영양소의 섭취는 보충되었으나 이와 함께 총 에너지 섭취가 증가하는 결과를 초래하였고, 지방의 에너지 비율은 여전히 높은 수준이었다. 여자대상자에서는 아침식사유형이 면식일 때 아침식사의 에너지 섭취수준이 낮았고 아침식사를 거르는 경우를 제외하고 미량영양소의 섭취가 부족할 가능성이 가장 높았다. 넷째, 식사유형별 식품섭취 양상에 차이를 나타내었으며 밥식인 경우 다른 주식유형에 비해 섭취하는 식품의 구성이 다양하였다. 위와 같은 결과는 주식의 종류 및 함께 섭취하는 식품의 구성과 그 다양성에 따라 영양섭취결과와 건강상태 지표상에 차이가 있으며, 성호르몬에 따른 성별 차이의 영향을 간과할 수 없음을 보여주었고, 나아가 주식의 선택과 식사의 구성에 미치는 사회경제적 수준의 영향이 고려되어야 할 것으로 생각되었다. 그러나 같은 유형의 주식을 중심으로 식사를 구성하더라도 식품의 선호도에 따라 다양한 구성이 가능하므로 궁극적으로는 건강한 식단에 대한 연구와 이에 대한 영양교육이 중요하며, 이때 생활환경과 성별에 따른 차이가 고려되어야 함을 확인할 수 있었다.

• 전자공학회논문지CI
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• 제47권1호
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• pp.30-40
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• 2010

IPTV 셋톱박스에서 가장 많이 사용하는 저장장치인 하드디스크는 가격에 비해 저장용량이 크고 입출력 속도가 빠르지만 스핀들 모터의 기계적 동작으로 인해 전력 소모가 많다는 단점이 있다. 셋톱박스에서 스트리밍 데이터를 재생하기 위하여 하드디스크의 스핀들 모터는 최대 전력을 사용하는 활성모드를 계속 유지해야 한다. 본 논문에서는 스트리밍 데이터 재생 시 전력 소모를 감소시키는 오프셋-버퍼링(Offset-Buffering)과 다중모드 스핀-다운(Multi Mode Spin-Down) 기법을 제안한다. 오프셋-버퍼링은 사용자의 시청 패턴을 분석하고 분석된 결과를 통해 버퍼링을 하므로 스핀들 모터의 모드를 대기모드로 길게 유지할 수 있다. 또한 오프셋 버퍼의 크기에 따라 다양한 모드로 스핀-다운을 하여 전력 소모를 줄일 수 있다. 실험 결과 본 논문에서 제안한 오프셋-버퍼링과 다중모드 스핀-다운은 기존의 풀-버퍼링(Full-Buffering)보다 28.3% 전력 소모량을 감소시켰으며, 스핀-업 횟수를 12.5% 줄였다.

• 상하수도학회지
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• 제36권3호
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• pp.149-165
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• 2022

The water consumption data of individual consumers must be analyzed and forecast to establish an effective water demand management plan. A k-mean cluster model that can monitor water use characteristics based on hourly water consumption data measured using automated meter reading devices and demographic factors is developed in this study. In addition, the quantification model that can estimate the daily water consumption is developed. K-mean cluster analysis based on the four clusters shows that the average silhouette coefficient is 0.63, also the silhouette coefficients of each cluster exceed 0.60, thereby verifying the high reliability of the cluster analysis. Furthermore, the clusters are clearly classified based on water usage and water usage patterns. The correlation coefficients of four quantification models for estimating water consumption exceed 0.74, confirming that the models can accurately simulate the investigated demographic data. The statistical significance of the models is considered reasonable, hence, they are applicable to the actual field. Because the use of automated smart water meters has become increasingly popular in recent year, water consumption has been metered remotely in many areas. The proposed methodology and the results obtained in this study are expected to facilitate improvements in the usability of smart water meters in the future.