• 전기학회논문지P
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• 제59권3호
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• pp.293-297
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• 2010

Next generation concentrating photovoltaic technologies could have a large-scale impact on world electricity production once they will become economically attractive and grid parity will be reached. Multi-junction solar cells will be characterised by a high value of the cell economical performance index if the cells were able to operate at high concentration level. Concentrating the sunlight by optical devices like lenses or mirrors reduces the area of expensive solar cells or modules, and, moreover, increases their efficiency. Accurate and reliable tracking is an important issue to maintain high the CPV system output power. Further, for high concentration CPV systems, the actual tracker cost is about 20% of the total CPV system cost. In this paper high-concentration is defined as systems using concentration ratios well above 100 times the one sun intensity and trackerlss CPV system studied. Using sphericalness lens and parallel MJ cell connection method were suggested and achieved experiment on a clear day in summer. Development of these high performance multi-junction CPV module promises to accelerate growth in photovoltaic power generation.

• 한국정보과학회논문지:데이타베이스
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• 제28권3호
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• pp.373-383
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• 2001

거리조인은 두 공간 데이터 집합 사이의 데이터쌍을 거리 상 가까운 순으로 검색하는 공간조인이다. 본 논문에서는 [1]에서 제시한 적응식 다단계 거리 조인 기법을 최적화하기 위한 기법들을 제안한다. 첫째, 평면 스위핑 축 선택을 위해 사용되는 스위핑 인덱스 공식을 최적화한다. 둘째, 노드쌍을 관리하는데 사용한 메인큐의 성능 향상을 위하여 노드쌍의 최대 거리값을 큐의 2차 우선 순위로 적용하는 기법을 제안한다. 또한, 균등 분포 및 비균등 분포 가정하의 한계 거리값 예측 기법의 장단점을 비교한다. 실험 결과는 제안하는 기법들을 통하여 알고리즘의 성능이 CPU 비용과 I/O 비용 면에서 크게 향상되었음을 보여준다.

• 한국습지학회지
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• 제8권2호
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• pp.83-92
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• 2006

본 연구에서는 습지의 가치 도출 방안으로 개발 사업 추진으로 인하여 습지 등 자연생태계가 훼손될 경우 이를 복원하는데 실제 소요된 비용을 파악하고, 회복과정에서 나타나는 생태과학적 지표인 생물종다양성지수를 이용하여 복원에 소요되는 한계비용 등을 산출함으로써 습지의 진정한 가치 도출에 기여해보고자 한다. 이는 경제적 분석에서 사용되는 두 가지 측면 중 하나인 비용 측면만으로는 훼손된 습지를 얼마만큼 복원해야 하는지 알 수 없음을 의미한다. 따라서 한계비용을 도출하여 복원비용을 파악하는 것이 습지관련 프로젝트를 진행하면서 보다 더 정확한 의사결정을 내릴 수 있을 것이다.

• 한국컴퓨터정보학회논문지
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• 제15권1호
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• pp.83-90
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• 2010

최대근접질의의 처리비용을 최적화하기 위해서는 색인에서 검색되는 노드의 수와 연산시간을 최소화할 수 있어야 한다. 이를 위해 최대근접질의 처리시 검색대상을 정확히 선택하고 객체들의 순환적 위치 속성이 고려된 검색거리 측도가 필요하다. 본 논문은 순환도메인을 갖는 검색공간에서 객체의 순환적 위치속성을 고려한 최대근접질의 처리방법을 제안하고 그 성능을 실험을 통하여 입증한다. 제안한 방법은 최대근접질의의 처리비용을 최적화하기 위한 검색거리 측도인 순환최소거리와 순환최적거리를 사용한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.1922-1940
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• 2019

IP address lookup is a function to determine nexthop for a given destination IP address. It takes an important role in modern routers because of its computation time and increasing Internet traffic. TCAM-based IP lookup approaches can exploit the capability of parallel searching but have a limitation of its size due to latency, power consumption, updatability, and cost. On the other hand, multibit trie-based approaches use SRAM which has relatively low power consumption and cost. They reduce the number of memory accesses required for each lookup, but it still needs several accesses. Moreover, the memory efficiency and updatability are proportional to the number of memory accesses. In this paper, we propose a novel architecture using an Indexed Multibit Trie (IMT) which is based on combined TCAM and SRAM. In the proposed architecture, each lookup takes at most two memory accesses. We present how the IMT is constructed so as to be memory-efficient and fast updatable. Experiment results with real-world forwarding tables show that our scheme achieves good memory efficiency as well as fast updatability.

• 대한의생명과학회지
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• 제26권4호
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• pp.275-287
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• 2020

Since its introduction in the forensic field, quantitative PCR (qPCR) has played an essential role in DNA analysis. Quality of DNA should be evaluated before short tandem repeat (STR) profiling to obtain reliable results and reduce unnecessary costs. To this end, various human DNA quantification kits have been developed. Among these kits, the PowerQunat® System was designed not only to determine the total amount of human DNA and human male DNA from a forensic evidence item, but also to offer data about degradation of DNA samples. However, a crucial limitation of the PowerQunat® System is its high cost. Therefore, to minimize the cost of DNA quantification, we evaluated kit performance using a reduced volume of reagents (1/2-volume) using DNA samples of varying types and concentrations. Our results demonstrated that the low-volume method has almost comparable performance to the manufacturer's method for human DNA quantification, human male DNA quantification, and DNA degradation index. Furthermore, using a reduced volume of regents, it is possible to run 2 times more reactions per kit. We expect the proposed low-volume method to cut costs in half for laboratories dealing with large numbers of DNA samples.

• 산업경영시스템학회지
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• 제43권4호
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• pp.33-40
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• 2020

In order to satisfy customers, it is important to identify the quality elements that affect customers' satisfaction. The Kano model has been widely used in identifying multi-dimensional quality attributes in this purpose. However, the model suffers from various shortcomings and limitations, especially those related to survey practices such as the data amount, reply attitude and cost. In this research, a model based on the text sentiment analysis is proposed, which aims to substitute the survey-based data gathering process of Kano models with sentiment analysis. In this model, from the set of opinion text, quality elements for the research are extracted using the morpheme analysis. The opinions' polarity attributes are evaluated using text sentiment analysis, and those polarity text items are transformed into equivalent Kano survey questions. Replies for the transformed survey questions are generated based on the total score of the original data. Then, the question-reply set is analyzed using both the original Kano evaluation method and the satisfaction index method. The proposed research model has been tested using a large amount of data of public IT service project evaluations. The result shows that it can replace the existing practice and it promises advantages in terms of quality and cost of data gathering. The authors hope that the proposed model of this research may serve as a new quality analysis model for a wide range of areas.

• Structural Engineering and Mechanics
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• 제82권5호
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• pp.557-569
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• 2022

The retrofit of existing structures in high seismic zones is a crucial issue in the earthquake engineering field. The interest of the research community is particularly high for the structures that do not respect current seismic codes and present structural deficiencies such as poor detailing and lack of capacity design provisions. A reinforced concrete (RC) school building is used as case study to show the influence of different knowledge levels on the seismic retrofitting cost assessment. The safety assessment of the case study building highlights deficiencies under both vertical and seismic loads. By considering all the possible knowledge levels defined by the Italian such as by the European codes in order to derive the mechanical properties of the school building constitutive materials, the retrofit operations are designed to achieve different seismic safety thresholds. The retrofit structural costs are calculated and summed up to the costs for in-situ in tests. The paper shows how for the case study building the major costs spent for a large number of in-situ tests allows to save a consistent amount of money for retrofit operations. The hypothesis of demolition and reconstruction of the building is also compared in terms of costs with all the analyzed retrofit options.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권6호
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• pp.1599-1618
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• 2024

Access control has always been one of the effective methods to protect data security. However, in new computing environments such as big data, data resources have the characteristics of distributed cross-domain sharing, massive and dynamic. Traditional access control mechanisms are difficult to meet the security needs. This paper proposes CACM-MMSR to solve distributed cross-domain access control problem for massive resources. The method uses blockchain and smart contracts as a link between different security domains. A permission decision model migration method based on access control logs is designed. It can realize the migration of historical policy to solve the problems of access control heterogeneity among different security domains and the updating of the old and new policies in the same security domain. Meanwhile, a semantic reasoning-based permission decision method for unstructured text data is designed. It can achieve a flexible permission decision by similarity thresholding. Experimental results show that the proposed method can reduce the decision time cost of distributed access control to less than 28.7% of a single node. The permission decision model migration method has a high decision accuracy of 97.4%. The semantic reasoning-based permission decision method is optimal to other reference methods in vectorization and index time cost.

• Asian-Australasian Journal of Animal Sciences
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• 제27권7호
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• pp.917-925
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• 2014

An accurate feed formulation is essential for optimizing feed efficiency and minimizing feed cost for swine and poultry production. Because energy and amino acid (AA) account for the major cost of swine and poultry diets, a precise determination of the availability of energy and AA in feedstuffs is essential for accurate diet formulations. Therefore, the methodology for determining the availability of energy and AA should be carefully selected. The total collection and index methods are 2 major procedures for estimating the availability of energy and AA in feedstuffs for swine and poultry diets. The total collection method is based on the laborious production of quantitative records of feed intake and output, whereas the index method can avoid the laborious work, but greatly relies on accurate chemical analysis of index compound. The direct method, in which the test feedstuff in a diet is the sole source of the component of interest, is widely used to determine the digestibility of nutritional components in feedstuffs. In some cases, however, it may be necessary to formulate a basal diet and a test diet in which a portion of the basal diet is replaced by the feed ingredient to be tested because of poor palatability and low level of the interested component in the test ingredients. For the digestibility of AA, due to the confounding effect on AA composition of protein in feces by microorganisms in the hind gut, ileal digestibility rather than fecal digestibility has been preferred as the reliable method for estimating AA digestibility. Depending on the contribution of ileal endogenous AA losses in the ileal digestibility calculation, ileal digestibility estimates can be expressed as apparent, standardized, and true ileal digestibility, and are usually determined using the ileal cannulation method for pigs and the slaughter method for poultry. Among these digestibility estimates, the standardized ileal AA digestibility that corrects apparent ileal digestibility for basal endogenous AA losses, provides appropriate information for the formulation of swine and poultry diets. The total quantity of energy in feedstuffs can be partitioned into different components including gross energy (GE), digestible energy (DE), metabolizable energy (ME), and net energy based on the consideration of sequential energy losses during digestion and metabolism from GE in feeds. For swine, the total collection method is suggested for determining DE and ME in feedstuffs whereas for poultry the classical ME assay and the precision-fed method are applicable. Further investigation for the utilization of ME may be conducted by measuring either heat production or energy retention using indirect calorimetry or comparative slaughter method, respectively. This review provides information on the methodology used to determine accurate estimates of AA and energy availability for formulating swine and poultry diets.