• JSTS:Journal of Semiconductor Technology and Science
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• 제5권4호
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• pp.262-269
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• 2005

Semiconductor scientists and engineers ideally desire the faster but the cheaper non-volatile memory devices. In practice, no single device satisfies this desire because a faster device is expensive and a cheaper is slow. Therefore, in this paper, we use heterogeneous non-volatile memories and construct an efficient hierarchy for them. First, a small RAM device (e.g., MRAM, FRAM, and PRAM) is used as a write buffer of flash memory devices. Since the buffer is faster and does not have an erase operation, write can be done quickly in the buffer, making the write latency short. Also, if a write is requested to a data stored in the buffer, the write is directly processed in the buffer, reducing one write operation to flash storages. Second, we use many types of flash memories (e.g., SLC and MLC flash memories) in order to reduce the overall storage cost. Specifically, write requests are classified into two types, hot and cold, where hot data is vulnerable to be modified in the near future. Only hot data is stored in the faster SLC flash, while the cold is kept in slower MLC flash or NOR flash. The evaluation results show that the proposed hierarchy is effective at improving the access time of flash memory storages in a cost-effective manner thanks to the locality in memory accesses.

• 한국정보과학회논문지:소프트웨어및응용
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• 제26권12호
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• pp.1404-1417
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• 1999

웹과 같은 분산 환경에서는, 웹 브라우저 상에서 SQL 형식의 공간 질의를 수행시키는 것과 또한 서버로부터 그 질의 결과를 보는 것이 가능하다. 그러나, 격자 이미지(raster image)와 같은 대용량 공간 데이타를 포함하는 질의 결과를 웹 브라우징할 때 발생하는 많은 문제점들 중에서, 사용자 응답 시간의 지연은 매우 중요한 문제이다. 본 논문에서는 사용자의 재요청(callback) 접근 패턴이 공간적 근접성(spatial locality)을 따른다는 가정하에서의, 사용자 응답 시간을 최소화하기 위한 새로운 프리페치(prefetch) 전략에 대해서 서술한다. 본 논문의 프리페치 전략은 다음과 같이 요약될 수 있다. 첫째, 프리페치 알고리즘은 사용자의 접근 패턴을 잘 반영하는 힐버트 곡선(Hilbert-curve) 모델을 바탕으로 한다. 둘째, 프리페치 전송 비용을 줄이기 위해서 사용자의 재요청 시간 간격(think time)을 이용한다. 본 논문에서는, 힐버트 곡선을 이용한 프리페치 전략의 성능 평가를 위해서 다양한 실험을 하였으며, 그 결과로 프리페치를 하지 않는 방식보다 높은 성능 향상이 있음을 보인다.Abstract In distributed environment(e.g., WWW), it would be possible for the users to submit SQL-like spatial queries and to see their query results from the server on the Web browser. However, of many obstacles which result from browsing query results including large spatial data such as raster image, the delay of user response time is very critical. In this paper we present a new prefetch policy which can alleviate user response time on the assumption that user's callback access pattern has spatial locality. Our prefetch policy can be summerized as follows: 1) our prefetch algorithm is based on the Hibert-curve model which well replects user's access pattern, and 2) it utilizes user's callback interval to reduce prefetch network transmission cost. In this paper we conducted diverse experiments to show that our prefetch policy achieves higher performance improvement compared to other non-prefetch methods.

• 융합경영연구
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• 제3권4호
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• pp.5-11
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• 2015

The study examined the socio-economic factors influencing the participation of rural farming households in barter trade in Ondo State, Nigeria. The objectives were to compare the socio-economic characteristics of the participants and non-participants in barter trade, analyze the preference for barter trade and identify the constraints to it. Also, the factors affecting respondents' participation in barter trade were identified. Empirical results indicated that there were significant differences in the socio-economic characteristics of the participants and non-participants in barter trade. The SWOT analysis showed that possession of agrarian attributes by the locality where the trade is practiced was the strongest factor ensuring the survival of barter in the study area. Double coincidence of wants was found to be the most prevailing weakness associated with barter while the major reason for participation by some households was that the quantity of commodities received is usually higher compared with cash transactions. Transportation cost to barter markets was found to be the greatest threat to the continued existence of barter trade in the area. The results of the Probit model showed that age, household size, transportation cost to cash markets, farm size, distance to barter markets, and formal education significantly affected the probability participating in barter trade.

• International Journal of CAD/CAM
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• 제5권1호
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• pp.29-38
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• 2005

A non-uniform 3-point ternary interpolatory subdivision scheme with variable subdivision weights is introduced. Its support is computed. The $C^0$ and $C^1$ convergence analysis are presented. To elevate its controllability, a modified edition is proposed. For every initial control point on the initial control polygon a shape weight is introduced. These weights can be used to control the shape of the corresponding subdivision curve easily and purposefully. The role of the initial shape weight is analyzed theoretically. The application of the presented schemes in designing smooth interpolatory curves and surfaces is discussed. In contrast to most conventional interpolatory subdivision scheme, the presented subdivision schemes have better locality. They can be used to generate $C^0$ or $C^1$ interpolatory subdivision curves or surfaces and control their shapes wholly or locally.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.61-67
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• 2020

This paper is to propose a hybrid memory adaptor using next-generation nonvolatile memory devices such as phase-change memory to improve the performance limitations of OpenStack-based object storage systems. The proposed system aims to improve the performance of the account and container servers for object metadata management. For this, the proposed system consists of locality-based dynamic page buffer, write buffer, and nonvolatile memory modules. Experimental results show that the proposed system improves the hit rate by 5.5% compared to the conventional system.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2011년도 춘계학술발표대회
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• pp.78-80
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• 2011

In the area of data fusion, dealing with heterogeneous data sources, numerous models have been proposed in last three decades to facilitate different application domains i.e. Department of Defense (DoD), monitoring of complex machinery, medical diagnosis and smart buildings. All of these models shared the theme of multiple levels processing to get more reliable and accurate information. In this paper, we consider five most widely acceptable fusion models (Intelligence Cycle, Joint Directors of Laboratories, Boyd control, Waterfall, Omnibus) applied to different areas for data fusion. When they are exposed to a real scenario, where large dataset from heterogeneous sources is utilize for object monitoring, then it may leads us to non-efficient and unreliable information for decision making. The proposed variation works better in terms of time and accuracy due to prior data diminution.

• Structural Engineering and Mechanics
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• 제89권4호
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• pp.375-381
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• 2024

In this paper, Eringen's nonlocal thermoelasticity is constructed to study wave propagation in a rotating two-temperature thermoelastic half-space. The problem is applied in the context of the dual-phase-lag (Dual) model, coupled theory (CD), and Lord-Shulman (L-S) theory. Using suitable non-dimensional fields, the harmonic wave analysis is used to solve the problem. Comparisons are carried with the numerical values predicted in the absence and presence of the gravity field, a nonlocal parameter as well as rotation. The present study is valuable for the analysis of nonlocal thermoelastic problems under the influence of the gravity field, mechanical force, and rotation.

• Environmental Engineering Research
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• 제25권2호
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• pp.147-162
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• 2020

The main objective of this study is to estimate the levels of pollution to which the community is presently exposed and to model the regimes of local air quality. Diurnal, daily, and monthly variations of NO, NO₂, SO₂, and O₃ were thoroughly investigated in three areas; namely, residential, industrial, and terminal in Ras Al-Khafji. There is obvious diurnal variation in the concentration of these pollutants that clearly follows the diurnal variation of atmospheric temperature and main anthropogenic and industrial activities. Correlation analysis showed that meteorological conditions play a vital role in shaping the pattern and transportation of air pollutants and photochemical processes affecting O₃ formation and destruction. Bivariate polar plots, an effective graphical tool that utilizes air pollutant concentrations' dependence on wind speed and wind direction, were used to identify prevailing emission sources. Non-buoyant ground-level sources like domestic heating and street transport emissions, various industrial stacks, and airport-related activities were considered dominant emission sources in observatory sites. This study offers valuable and detailed information on the status of air quality, which has considerable, quantifiable, and important public health benefits.

• 한국응용곤충학회지
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• 제34권3호
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• pp.243-248
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• 1995

효과적인 미생물 제제로 사용할 수 있는 Bacillus thuringiensis 균주들을 분리하기 위하여 경기도 일원의 72군데의 저곡창고에서 먼지를 채취하여 B. thuringiensis의 분포와 독성을 조사하였다. 총 411개의 채취된 저곡창고의 먼지에서 포자와 내독소 단백질을 생산하는 146개에 이르는 많은 수의 B. thuringiensis가 분리되었다. 저곡창고에서 분리된 146개 Bt의 독성 분포는 나비목의 누에 (Bombyx mori)유충에 독성을 띠는 균주가 84%로 가장 많이 분리되었고, 파리목의 빨간 집모기(Culex pipiens)유충에는 3%, 나비목과 파리목에 동시에 독성을 띠는 균주는 1%였다. 그러나 딱정벌레목의 쌀바구미(Sitophitus oryzae)에 독성을 띠는 균주는 분리되지 않았으며, 내독소 단백질은 형성하지만 독성을 띠지 않는 B. thuringiensis가 12%의 비율로 분리되어 흔히 존재함을 알 수 있었다. 이상의 결과로서 저곡창고는 B. thuringiensis의 유리한 분리장소임을 알 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4795-4800
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• 2013

The involvement of non-government organizations (NGOs) and support groups has helped strengthen public health services in addressing cancer care burden. Owing to the contribution of volunteers in cancer care, this article documents a qualitative study that examined challenges in attracting and retaining cancer care volunteers as part of the effort to develop a volunteer recruitment model. Data were collected through three focus group discussions involving 19 cancer support group members in Malaysia. Findings of the study revealed that mobility and locality appeared to be significant in Malaysian context, while the need for financial support and time flexibility are challenges faced by cancer support groups to attract and retain volunteers. The findings imply that cancer care initiatives can benefit from more local volunteers but at the same time these volunteers require flexibility and financial support to sustain their engagement.