• Journal of Bio-Environment Control
• /
• v.28 no.1
• /
• pp.46-54
• /
• 2019

Experiments of local cooling and heating on crown and root zone of forcing cultivation of strawberry 'Seolhyang' using heat pump and root pruning before planting were conducted. During the daytime, the crown surface temperature of the crown local cooling treatment was maintained at $18{\sim}22^{\circ}C$. This is suitable for flower differentiation, while those of control and root zone local cooling treatment were above $30^{\circ}C$. Budding rate of first flower clusters and initial yields were in the order of crown local cooling, root zone local cooling and control in root pruning plantlet and non pruning plantlet, except for purchase plantlet. Those of root pruning plantlet were higher than those of non pruning plantlet. These trends were evident in the yield of the first flower cluster until February 14, 2018, and the effect of local cooling and root pruning decreased from March 9, 2018. The budding rates of the second flower cluster according to the local cooling and root pruning treatments were not noticeable compared to first flower cluster but showed the same tendency as that of first flower cluster. In the heating experiment, root zone local heating(root zone $20^{\circ}C$+inside greenhouse $5^{\circ}C$) and crown local heating(crown $20^{\circ}C$+inside greenhouse $5^{\circ}C$) saved 59% and 65% of heating fuel, respectively, compared to control(inside greenhouse $9^{\circ}C$). Considering the electric power consumption according to the heat pump operation, the heating costs were reduced by 55% and 61%, respectively.

• Journal of KIISE:Computer Systems and Theory
• /
• v.37 no.5
• /
• pp.292-303
• /
• 2010

On-chip cache memories play an important role in both performance and energy consumption points of view in resource-constrained embedded systems by filtering many off-chip memory accesses. We propose a 2-level data cache architecture with a low energy-delay product tailored for the embedded systems. The L1 data cache is small and direct-mapped, and employs a write-through policy. In contrast, the L2 data cache is set-associative and adopts a write-back policy. Consequently, the L1 data cache is accessed in one cycle and is able to provide high cache bandwidth while the L2 data cache is effective in reducing global miss rate. To reduce the penalty of high miss rate caused by the small L1 cache and power consumption of address generation, we propose an ECP(Early Cache hit Predictor) scheme. The ECP predicts if the L1 cache has the requested data using both fast address generation and L1 cache hit prediction. To reduce high energy cost of accessing the L2 data cache due to heavy write-through traffic from the write buffer laid between the two cache levels, we propose a one-way write scheme. From our simulation-based experiments using a cycle-accurate simulator and embedded benchmarks, the proposed 2-level data cache architecture shows average 3.6% and 50% improvements in overall system performance and the data cache energy consumption.

• The Journal of the Korea Contents Association
• /
• v.8 no.5
• /
• pp.72-81
• /
• 2008

High Performance DSP usually supports cache and internal memory. For an optimal implementation of a multimedia stream application on such a high performance DSP, one needs to utilize the cache and internal memory efficiently. In this paper, we investigate performance analysis of cache, and internal memory configuration and placement necessary to achieve an optimal implementation of multimedia stream applications like motion picture encoder on high performance DSP, TMS320C6000 series, and propose strategies to improve performance for cache and internal memory placement. From the results of analysis and experiments, it is verified that 2-way L2 cache configuration with the remaining memory configured as internal memory shows relatively good performance. Also, it is shown that L1P cache hit rate is enhanced when frequently called routines and routines having caller-callee relationships with them are continuously placed in the internal memory and that L1D cache hit rate is enhanced by the simple change of the data size. The results in the paper are expected to contribute to the optimal implementation of multimedia stream applications on high performance DSPs.

• Journal of Internet Computing and Services
• /
• v.16 no.5
• /
• pp.19-27
• /
• 2015

Due to the advantages of fast read/write operation and low power consumption, SSD(Solid State Drive) is now widely adopted as storage device of smart phone, laptop computer, server, etc. However, the shortcomings of SSD such as limited number of write operations and asymmetric read/write operation lead to the problem of shortened life span of SSD. Therefore, the block replacement policy of SSD used as cache for HDD is very important. The existing solutions for improving the lifespan of SSD including the LARC scheme typically employ the LRU algorithm to manage the SSD blocks, which may increase the miss rate in SSD due to the replacement of frequently used block instead of rarely used block. In this paper we propose a novel block replacement scheme which considers the block reuse interval to effectively handle various data read/write patterns. The proposed scheme replaces the block in SSD based on the recency decided by reuse interval and age along with hit ratio. Computer simulation using workload trace files reveals that the proposed scheme consistently improves the performance and lifespan of SSD by increasing the hit ratio and decreasing the number of write operations compared to the existing schemes including LARC.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04b
• /
• pp.145-147
• /
• 2004

본 논문에서는 무선인터넷 환경에 적합한 개인화된 상품추천에이전트를 제안한다. 기존에 유선인터넷상의 많은 개인화 추천시스템에서는 초기 사용자 모델링을 위해 사용자에게 수많은 질의를 하고 응답을 요구하였다. 그러나 이러한 방식은 무선인터넷 환경에서 정보 전송량에 따른 높은 사용요금을 고려할 때 적용하기 힘든 방식이다. 본 제안 시스템은 사용자의 Social data률 이용하여 사용자를 비슷한 연령과 성별 그룹으로 나누고, 해당 그룹에서 구매율이 높은 상품을 우선 제시한 후, 사용자 행동을 모니터링 하여 암시적(Implicit)피드백을 통해 프로파일을 생성함으로써, 번거로운 질의-응답 과정 없이도 초기 사용자 모델링을 수행할 수 있다. 프로파일 생성 이후에는 이를 기반으로 하여 사용자몰 유사한 취향을 가진 그룹으로 다시 군집화한 후 협력적 추천을 하게 되며, 프로파일에는 해당 상품의 최종 카테고리명과 키워드를 수집함으로써, 상품의 브랜드와 규격정보를 반영한 추천이 가능하다. 또한 추천 상품과 사용자의 구매데이터와의 비교를 수행하여 사용자가 해당상품을 구매하였을 경우, 상품에 대한 취향정보는 그대로 유지하고 관련 상품을 추천하되, 구매한 상품이 중복 추천되지 않도록 하였다. 시스템 평가를 위해 프로토타입을 구현하여, 다수의 사용자에게 시스템을 이용하며 관심품목을 체크하도록 하였고. 추천횟수가 반복되며 히트율이 증가하는 결과를 통해 시스템의 학습속도와 성능을 평가하였다. 그리고 쇼핌몰에서 구매경험이 있는 사용자의 기존 구매데이터와 Social data를 이용한 초기 제시상품을 역으로 비교하여 오랜 시간과 비용 발생 없이도 초기 프로파일 생성의 유효성을 증명하였다. 포함하는 XML 질의에 대해서도 웹에서 캐쉬를 이용한 처리가 효율적임을 확인하였다.키는데 목적이 있다.RED에 비해 향상된 성능을 보여주었다.웍스 네트워크상의 다양한 디바이스들간의 네트워크 다양화와 분산화 기능을 얻을 수 있었고, 기존의 고가의 해외 솔루션인 Echelon사의 LonMaker 소프트웨어를 사용하지 않고도 국내의 순수 솔루션인 리눅스 기반의 LonWare 3.0 다중 바인딩 기능을 통해 저 비용으로 홈 네트워크 구성 관리 서버 시스템 개발에 대한 비용을 줄일 수 있다. 기대된다.e 함량이 대체로 높게 나타났다. 점미가 수가용성분에서 goucose대비 용출함량이 고르게 나타나는 경향을 보였고 흑미는 알칼리가용분에서 glucose가 상당량(0.68%) 포함되고 있음을 보여주었고 arabinose(0.68%), xylose(0.05%)도 다른 종류에 비해서 다량 함유한 것으로 나타났다. 흑미는 총식이섬유 함량이 높고 pectic substances, hemicellulose, uronic acid 함량이 높아서 콜레스테롤 저하 등의 효과가 기대되며 고섬유식품으로서 조리 특성 연구가 필요한 것으로 사료된다.리하였다. 얻어진 소견(所見)은 다음과 같았다. 1. 모년령(母年齡), 임신회수(姙娠回數), 임신기간(姙娠其間), 출산시체중등(出産時體重等)의 제요인(諸要因)은 주산기사망(周産基死亡)에 대(對)하여 통계적(統計的)으로 유의(有意)한 영향을 미치고 있어 $25{\sim}29$세(歲)의 연령군에서, 2번째 임신과 2번째의 출산에서 그리고 만삭의 임신 기간에, 출산시체중(出産時體重) $3.50{\sim}3.99kg$사이의 아

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.4
• /
• pp.56-66
• /
• 2021

In this study, a waste heat recovery system was devised and the performances of components incorporated to recover the heat generated during the processing of aerobic liquid-composting in a livestock manure treatment facility were analyzed. In addition, the availability of recovered heat was confirmed. The heat generated by liquid fermentation in the livestock manure treatment facility was also checked. Experimental temperatures were set at 35, 40, and 45 ℃ based on considerations of the uniformity of aerobic liquid-composting fermentation tank temperature and its operating range (34.5 ~ 43.9 ℃). Recovered heat energies from the combined heat exchanger, which consisted of PE and STS pipes, were 53.5, 65.6, 74.4 MJ/h, The heat pump of capacity 5 RT was heated at 95.6, 96.1, 98.9 MJ/h and the heating COPs of the pump were 4.53, 4.62, and 4.65, respectively. The maximum hot water production capacity of the heat exchanger assuming a fermentation tank temperature of 45 ℃ confirmed an energy supply of 56 360 kcal/day. The heating capacity of the FCU linked to the heat storage tank was 20.8 MJ/h, and the energy utilization efficiency was 96.1%. When livestock manure was dried using the FCU, it was confirmed that the initial function rate was reduced by 50.5 to 45.8 % after drying.

• Journal of the Korean Geotechnical Society
• /
• v.26 no.2
• /
• pp.45-54
• /
• 2010

The SCW numerical model described in the companion paper was used to carry out a comprehensive parametric study to evaluate the performance of the SCW. The five ground related parameters, which are porosity, hydraulic conductivity, thermal conductivity, specific heat, geothermal gradient, and five SCW design parameters, which are pumping rate, well depth, well diameter, dip tube diameter, bleeding rate, were used in the study. Two types of numerical simulations were performed. The first type was used to perform short-term (24-hour) simulation, while the second type 14 day simulation. The study results indicate that the parameters that have important influence on the performance of SCW were hydraulic conductivity, thermal conductivity, geothermal gradient, pumping rate, and bleeding rate. The thermal conductivity had the most important influence on the performance of the SCW. With the increase in the geothermal gradient, the performance increased in the heat mode, but decreased in the cooling mode. The hydraulic conductivity influenced the performance when the value was larger than $10^{-4}m/s$. The depth of the well increased the performance, but at the cost of increased cost of boring. The bleeding had an important influence on SCW, greatly enhancing the performance at a limited increased cost of operation. Overall, this study showed that various factors had a cumulative influence on the performance of the SCW, and a numerical simulation can be used to accurately predict the performance of the SCW.

• Journal of Bio-Environment Control
• /
• v.17 no.2
• /
• pp.90-95
• /
• 2008

It has become a big matter of concerns that the skill and measures against reduction of energy and cost for heating a protected horticultural greenhouse were prepared. But in these days necessity of cooling a protected horticultural greenhouse is on the rise from partial high value added farm products. In this study, therefore, a horizontal type geothermal heat pump system with 10 RT scale to heat and cool a protected horticultural greenhouse and be considered to be cheaper than a vertical type geothermal heat pump system was installed in greenhouse with area of $240\;m^2$. And cooling performances of this system were analysed. As condenser outlet temperature of heat transfer medium fluid rose from $40^{\circ}C$ to $58^{\circ}C$, power consumption of the heat pump was an upturn from 11.5 kW to 15 kW and high pressure rose from 1,617 kPa to 2,450 kPa. Cooling COP had the trend that the higher the ground temperature at 1.75 m went, the lower the COP went. The COP was 2.7 at ground temperature at 1.75 m depth of $25.5^{\circ}C$ and 2.0 at the temperature of $33.5^{\circ}C$ and the heat extraction rate from the greenhouse were 28.8 kW, 26.5 kW respectively at the same ground temperature range. 8 hours after the heat pump was operated, the temperature of ground at 60 cm and 150 cm depth buried a geothermal heat exchanger rose $14.3^{\circ}C$, $15.3^{\circ}C$ respectively, but the temperature of ground at the same depth not buried rose $2.4^{\circ}C$, $4.3^{\circ}C$ respectively. The temperature of heat transfer medium fluid fell $7.5^{\circ}C$ after the fluid passed through geothermal heat exchanger and the fluid rejected average 46 kW to the 1.5 m depth ground. It analyzed the geothermal heat exchanger rejected average 36.8 W/m of the geothermal heat exchanger. Fan coil units in the greenhouse extracted average 28.2 kW from the greenhouse air and the temperature of heat transfer medium fluid rose $4.2^{\circ}C$after the fluid passing through fan coil units. It was analyzed the accumulation energy of thermal storage thank was 321 MJ in 3 hours and the rejection energy of the tank was 313 MJ in 4 hours.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2136-2141
• /
• 2007

The Loop Heat Pipe(LHP) system uses capillary forces so as to pump the working fluid from heat acquisition to heat rejecting systems. The performance of the LHP systems depends mainly upon the operating performance of the wick structure. The capillary pressure increases with decreasing the pore size of the wick structure. By the way, the wick structure's permeability decreases with decreasing the pore size and the porosity. To obtain an ideal wick, the wick structure should possess several characteristics such as the small pore size, high porosity and chemical compatibility with working fluid. Sintered metal wicks have been mainly used as the capillary wick structure mounted in LHP because of the fact that the sintered metal wick has some advantages like convenient selection of wick material, smaller pore size and so on as well as high reliability. In this study, sintered metal wicks were developed to meet required several parameters to design the high performance LHP systems for obtaining even more effective cooling technologies.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.10
• /
• pp.1020-1025
• /
• 2010

On-board black body is used for radiation temperature calibration of spaceborne radiometers and imaging systems. The thermal design of black body proposed in this study is basically composed of heaters to heat-up the black body from low to high temperature during the calibration, heat pipe to transfer residual heat on the black body just after calibration to radiator on the S/C and heaters on the radiator to keep the certain temperature range of the black body during non-calibration. In the present work, the effectiveness of thermal design of on-board black body has been investigated by on-orbit thermal analysis.