• Journal of Information Processing Systems
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• 제11권3호
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• pp.483-494
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• 2015

High Efficiency Video Coding (HEVC) is the most recent video codec standard of the ITU-T Video Coding Experts Group and the ISO/IEC Moving Picture Experts Group. The main goal of this newly introduced standard is for catering to high-resolution video in low bandwidth environments with a higher compression ratio. This paper provides a performance comparison between HEVC and H.264/AVC video compression standards in terms of objective quality, delay, and complexity in the broadcasting environment. The experimental investigation was carried out using six test sequences in the random access configuration of the HEVC test model (HM), the HEVC reference software. This was also carried out in similar configuration settings of the Joint Scalable Video Module (JSVM), the official scalable H.264/AVC reference implementation, running on a single layer mode. According to the results obtained, the HM achieves more than double the compression ratio compared to that of JSVM and delivers the same video quality at half the bitrate. Yet, the HM encodes two times slower (at most) than JSVM. Hence, it can be concluded that the application scenarios of HM and JSVM should be judiciously selected considering the availability of system resources. For instance, HM is not suitable for low delay applications, but it can be used effectively in low bandwidth environments.

• 전력전자학회논문지
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• 제20권4호
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• pp.337-343
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• 2015

The multi-level inverters are highly efficient for high-power and medium-voltage AC driving applications, such as high-speed railway systems and renewable energy resources, because such inverters generate lower total harmonic distortion (THD) and electromagnetic interface (EMI). Lower switching stress occurs on switching devices compared with conventional two-level inverters. Depending on the multi-level inverter topology, the required components and number of switching devices are different, influencing the overall efficiency. Comparative studies of multi-level inverters based on loss analysis and output characteristic are necessary to apply multi-level inverters in high-power AC conversion systems. This paper proposes a theoretical loss analysis method based on piecewise linearization of characteristic curves of power semiconductor devices as well as loss analysis and output performance comparison of five-level neutral-point clamped, flying capacitor inverters, and high-level cascaded H-bridge multi-level inverters.

• 동력기계공학회지
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• 제18권6호
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• pp.120-125
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• 2014

In this paper, suitable working fluid of 1MW Organic Rankine Cycle(ORC) with liquid-vapor ejector using effluent from power plant is selected. The results of comparison performance of 5 refrigerants are as follows; R600a, R134a, R1270, R236fa, R235fa. The operating parameters considered in this study include the condensation capacity evaporation capacity and efficiency. As a result of comparison of basic ORC system and with liquid-vapor ejector, with ORC system presents the higher system efficiency since the ejector makes the turbine outlet pressure lower than condensation pressure through its pressure recovery. Also, this ejector ORC system is advantageous in miniaturizing the size of components owing to decrease of evaporation capacity and condensation capacity.

• 한국농공학회논문집
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• 제59권3호
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• pp.97-110
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• 2017

This study investigates the efficiencies of machine learning models, including artificial neural network (ANN), generalized regression neural network (GRNN), adaptive neuro-fuzzy inference system (ANFIS) and random forest (RF), for reservoir water level forecasting in the Chungju Dam, South Korea. The models' efficiencies are assessed based on model efficiency indices and graphical comparison. The forecasting results of the models are dependent on lead times and the combination of input variables. For lead time t = 1 day, ANFIS1 and ANN6 models yield superior forecasting results to RF6 and GRNN6 models. For lead time t = 5 days, ANN1 and RF6 models produce better forecasting results than ANFIS1 and GRNN3 models. For lead time t = 10 days, ANN3 and RF1 models perform better than ANFIS3 and GRNN3 models. It is found that ANN model yields the best performance for all lead times, in terms of model efficiency and graphical comparison. These results indicate that the optimal combination of input variables and forecasting models depending on lead times should be applied in reservoir water level forecasting, instead of the single combination of input variables and forecasting models for all lead times.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.19-29
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• 2022

The 2D/1D method has become the mainstream of the direct transport calculation considering the balance of accuracy and efficiency. However, the 2D/1D method still suffers from stability issues. Recently, a quasi-3D method has been proposed with axial Legendre expansion. Analysis and comparison of the 2D/1D and quasi-3D method is conducted in theory from the equation derivation. Besides, the C5G7 benchmark, the KUCA benchmark and the macro BEAVRS benchmark are calculated to verify the theory comparisons of these two methods with the direct transport code SHARK. All results show that the quasi-3D method has better stability and accuracy than the 2D/1D method with worse efficiency and memory cost. It provides a new option for direct transport calculation with the quasi-3D method.

• 디자인학연구
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• 제18권3호
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• pp.15-24
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• 2005

충분한 디자인 전문인력을 갖추지 못한 중소기업에서 부적절한 제품디자인 개발과정으로 인하여 시간, 비용, 생산적 측면에서 많은 낭비와 시행착오가 발생하고 있다. 특히 디자인 프로세스에서 가장 중시하는 구상단계의 디자인 컨셉 도출이나 전개단계의 스케치 및 렌더링의 진행을 통한 의사결정에 있어서 객관적이고, 과학적인 접근방법은 제고되지 않고 있으며, 이의 개선을 위한 연구도 매우 드물다. 이에 본 연구에서는 이와 같은 체계적이지 못한 의사결정단계의 보완 및 정량화 된 데이터의 산출을 통한 리스크 감소를 위해 디자인 프로세스의 전개단계 및 결정단계에 AHP기법과 쌍대분석법의 개념을 적용하였다. AHP기법의 기본 개념은 쌍대비교에서 출발한다. 일반적으로 인간은 절대적 판단보다는 상대적 판단에 의한 의사결정을 보다 효율적으로 수행할 수 있으며, 쌍대비교는 이와 같은 인간 특성에 바탕을 두고 스케치 대안들을 두개의 대안끼리 짝을 지어 비교하는 상대적 비교개념을 사용하고 있다. 따라서 디자이너들의 디자인 스케치 대안비교에 있어서 보다 효율적인 판단을 유도할 수 있으며 여러 대안들에 대한 평가를 일관성 있게 수행할 수 있도록 도와줌으로서 의사결정의 효율향상과 최종 디자인 선택시의 리스크를 상당부분 감소시킬 수 있는 것이다. 그리고 각 대안들의 정량적인 순위를 도출하고 여러 감성적인 디자인 결과물들에 대하여 100% 정확한 디자인 대안의 선택은 아니지만 여러 디자인 대안들의 필터링과 의사결정을 수 행함에 있어서 기존의 방법보다는 개선되어 정량적이고 일관적인 기준을 제공해주는 것이며, 상당부분에 있어서 개성과 감성의 차를 극복하는 효율적인 방법이 될 것이고 연구 의의도 여기에 있다 하겠다. 끝으로 품질개선을 위한 기법적용의 연구결과에 대해서는 실제 디자인 개발 아이템의 사례연구를 통하여 타당성을 검증하고, 이상의 품질 개선을 위한 기법이 적용된 이상적인 신 프로세스를 제안하고자 한다.

• 한국병원경영학회지
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• 제7권1호
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• pp.64-87
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• 2002

The purpose of this study is aimed to grasp the factors, which may influence the harmonized organizational efficiency of the objects of hospital structure as well as its structural constituents of each departments of administration, nursing, and para-medical personnels, in order to provide basic data enable to contribute in the development of hospital. The survey data involved in the study was derived from 385 personnels working in 5 medium and small sized hospitals in Seoul area. The main finding of the study can be summarized as follows; 1. The organizational efficiency in accordance with the general characteristics of subjects in order of male, over 30 years of age, university graduates, long-term tenure and high position is higher, whereas, in as much as wage and well trained personnels in administration departments are higher, its organizational efficiency is higher in comparison with those of nursing and para-medical departments. 2. The organizational efficiency in accordance with satisfaction and the motive contributional factors is higher as much as the high satisfactory level in every departments in general. 3. The organizational efficiency in accordance with the factors of job characteristics is higher in as much as difficulty of the jobs is lesser, however there was not statically significance between administration and para-medical departments. In as much as the job circulation is intact, job standard level is higher and the more job responsibility the higher organizational efficiency, while the more workload and the more work feud resulted lower organizational efficiency. It was obvious that the higher professional expertise as well as the training and application level are improving the organizational efficiency. 4. The organizational efficiency in accordance with the factors of structural characteristics was higher in as much as the intercommunication was smooth and the structural formalization level are higher, however there was not statically significance between the participation level of decision making and the organizational efficiency. 5. In as much as higher educational level of over university graduates, management of organization and the job level are satisfied, the psychological motive contributional level is higher, while the lesser job difficulty, the smooth job performance, the higher level of professional expertise, the higher structural formalization level, the smooth intercommunication, have affected as major influence factors of the structural characteristics of organizational efficiency. 6. As the management of hospital organization, the job level and personal relation are satisfied or psychological motive is provided, especially when there are no difficult jobs or smooth job circulation and no job feud are prevailing, it was apparent that the organizational efficiency is improving accordingly. The nursing departments has high educational standard and is satisfied in the management and job level of hospital organization as there are no difficult jobs while the level of hospital's organizational formality is high and the intercommunication is smooth, which are improving the organizational efficiency. The para-medical departments is also satisfied the management and job level of hospital organization and it was apparent that the organizational efficiency is higher in as much as the level of job standardization is high and the intercommunication is smooth. As a result of this study, in order for improving the organizational efficiency of the medium and small sized hospitals, the management and job level as well as personal relation are preferably satisfied, whereas the level of job circulation, job responsibility, the expertise and formalization of organization, intercommunication and etc. should be satisfied, and, therefore, it is advisable to buildup discriminated organizational management and environment for different division on the basis above factors. Since this study is carried on several hospitals in Seoul area, there is a certain limit to generalize its result to all domestic hospitals, nevertheless the gallop poll was made by developing the questionnaires with reasonability and reliability. Especially, as the study was carried by analyzing the comparison of influence factors' difference of organizational efficiency in accordance with the divisional characteristics of the medium and small sized hospitals.

• 수산해양기술연구
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• 제27권4호
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• pp.286-292
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• 1991

현재 사용되고 있는 전개판의 성능을 보다 향상시키기 위한 방안으로 비행기의 익이론에 기초를 두고, 전개판의 경계층을 흡입하거나 제거하는 방법 중에서 역류역을 제거하는 와발생기의 부착을 전개판에 적용하였다. 성능분석을 위해서 단순만곡형, V-만곡형 그리고 슬롯만곡형 전개판의 3종에 와발생기를 부착하지 않은 경우와 부착한 경우에 대하여 성능 및 유체역학적 특성을 성능실험과 가시화실험을 통하여 비교해 보았다. 실험결과를 요약하면 다음과 같다. \circled1 단순만곡형전개판에 와발생기를 부착한 경우 최대전개력계수는 10~15% 증가, 항력계수는 2%미만증가, 양항비는 5~20% 증가하였다. \circled2 V-만곡형전개판에 와발생기를 부착한 경우 양항비가 10~20% 증가하였다. \circled3 슬롯만곡형에 와발생기를 부착한 경우 영각 20$^{\circ}$ 이내에서 최대전개력계수는 약 20%이상 증가, 항력계수는 5~20% 증가, 양항비는 약간 높게 나타났으나, 영각 25$^{\circ}$이상에서는 이들 계수의 값들이 기준형에 비하여 낮게 나타났다. \circled4 와발생기를 부착한 전개판에서 박리점이 기준형에 비하여 다소 후연에 나타났다. \circled5 와발생기에 따른 전.후면의 유속차는 단순만곡형의 경우 모든 영각에서 약 10% 증가, V-만곡형의 경우 전반적으로 증가하였으나 영각 25$^{\circ}$에서는 비슷하게, 슬롯만곡형의 경우 영각 25$^{\circ}$까지는 증가하는 것으로 나타났다. \circled6 와발생기에 따른 박리역의 크기는 단순만곡형에서 약 5~15% 감소, V-만곡형과 슬롯만곡형은 영각 15$^{\circ}$~20$^{\circ}$에서는 약 10% 감소, 영각 25$^{\circ}$ 이상일 때는 비슷하게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권11호
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• pp.1572-1576
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• 2003

A growth trial of 180 days was conducted on 18 crossbred calves (6-9 months, $73.48{\pm}6.52kg)$ by randomly allotting to two complete diets and a conventional diet (6 in each group). The complete diets were formulated containing 40 per cent cotton straw, one processed in mash form and other subjected to expander-extruder pelletization (EEP). These two complete diets were compared with conventional system of feeding under which concentrate mixture and cotton straw were fed separately in a 60:40 ratio. The calves on EEP complete diet consumed more (p<0.01) DM in comparison to other two groups. The DMI per 100 kg body weight was similar among all the diets. The ADG was significantly (p<0.01) higher in calves fed EEP complete diets (815.4 g) followed by mash (627.0 g) in comparison to conventional diet (464.9 g). The DM intake per kg metabolic body weight was higher (p<0.01) on complete diet than conventional diet. The intakes of DCP (p<0.05), TDN (p<0.01), and ME (p<0.01) per kg metabolic body weight were significantly higher on EEP complete diet in comparison to mash and conventional diet. The water intake per kg DM intake was comparable among all the diets. The efficiency of DM utilisation was higher p (<0.05) on EEP complete diet (5.84) in comparison to conventional diet (7.41), whereas on mash diet it was intermediate (6.68). The efficiency of DCP utilization was similar in mash and EEP complete diet fed groups, which was higher (p<0.05) than that of the conventional diet. Expander-extrusion though increased the cost of production it reduced the cost of feed per unit live weight gain by 12.28% in comparison to its mash form and by 16.76% when concentrate and cotton straw were fed separately. The results indicated that blending of cotton straw along with concentrates in a complete diet increased the palatability of the straw in comparison to conventional system and expander extruder processing of cotton straw based complete diet gave better growth performance and may form an economic ration for growing crossbred calves.

• 대한한의학방제학회지
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• 제22권2호
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• pp.45-54
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• 2014

Objectives : The main objective of this study is to classify herbal components to 4 groups which are similar to Gunsinjwasa grades by using herbal composition ratio of prescription. Another objective is to design the searching system which compares prescriptions and improves efficiency with 4 groups like Gunsinjwasa grades. Methods : This study was proceeded with Acess 2007 on Microsoft Windows 7 and we created composition ratio based on weight by using prescriptions of Donguibogam, Uihagipmun and Banghakhabpyun. We could make comparison and searching method of prescriptions. Results : We could search using composition ratio degree of herbs which composes prescription. And the similarity comparison of prescription was possible with value from 0 to 10. Conclusions : We could increase the accuracy of the searching prescriptions and comparison with putting into the information about composition degree and composition ratio of herbs which compose a prescription.