• ETRI Journal
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• 제42권4호
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• pp.608-618
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• 2020

We present a novel GPU-based ray-casting algorithm for volume rendering of unstructured grid data. Our volume rendering system uses a ray-casting method that guarantees accurate rendering results. We also employ the per-pixel intersection list concept in the Bunyk algorithm to guarantee an accurate result for non-convex meshes. For efficient memory access for the lists on the GPU, we represent the intersection lists for all faces as an array with our novel construction algorithm. With the intersection lists, we perform ray-casting on a GPU, and a GPU thread handles each ray. To increase ray-coherency in a thread block and improve memory access efficiency, we extend a prior image-tile-based work distribution method to fit modern GPU architectures. We also show that a prior approach using a per-thread local buffer to reduce redundant computation is not appropriate for modern GPU architectures. Instead, we take an on-demand calculation strategy that achieves better performance even though it allows duplicate computations. We applied our method to three unstructured grid datasets with different characteristics. With a GPU, our method achieved up to 36.5 times higher performance for the ray-casting process and 19.7 times higher performance for the whole volume rendering process compared with the Bunyk algorithm using a CPU core. Also, our approach showed up to 8.2 times higher performance than a GPU-based cell projection method while generating more accurate rendering results. These results demonstrate the efficiency and accuracy of our method.

• 보건행정학회지
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• 제10권4호
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• pp.116-143
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• 2000

Considerable attention has been devoted in the accounting literature to identify the factors that cause or drive the costs of overhead activities. This paper extends recent cost driver research to the health care provider. In various case studies, it has been suggested that overhead costs are driven by volume and complexity variables. This paper investigates the significance of these variables in determining hospital overhead costs, how they are structurally related and how the cost impacts of these variables can be estimated in practice. This paper analyzes the determinants of hospital costs using the sample of South Korea hospitals for seven year during the period 1952－1997. The paper focuses on the extent to which hospital overhead costs depend on complexity, efficiency in addition to depending on more conventional volume based measures of hospital activity. The results of regression analysis suggest that volume and complexity factors positively and significantly affect overhead costs in the hospital industry. The results show that the complexity-related cost drivers strongly affected on the overhead costs in tile health care provider industry more than manufacturing industry which is mainly affected by volume-related cost drivers. That means each Industry may have different cost structures. Therefore it Is Important to find their proper cost structures and cost drivers and use them. Futhermore identification of overhead or indirect cost drivers is likely to be particularly useful in heath care. The identification of cost drivers can be of benefit to all health care stakeholders because these facilitates more efficient management of the national resources devoted to health care. While this study has documented that the level of service complexity is a significant determinant of hospital overhead costs, caution should be exercised in interpreting this as supportive of the cost accounting procedures associated with ABC. It is an open question whether even a well-designed ABC system will provide suitable proxies for marginal costs for decision making purposes.

• Molecules and Cells
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• 제37권8호
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• pp.575-584
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• 2014

Potassium is a macronutrient that is crucial for healthy plant growth. Potassium availability, however, is often limited in agricultural fields and thus crop yields and quality are reduced. Therefore, improving the efficiency of potassium uptake and transport, as well as its utilization, in plants is important for agricultural sustainability. This review summarizes the current knowledge on the molecular mechanisms involved in potassium uptake and transport in plants, and the molecular response of plants to different levels of potassium availability. Based on this information, four strategies for improving potassium use efficiency in plants are proposed; 1) increased root volume, 2) increasing efficiency of potassium uptake from the soil and translocation in planta, 3) increasing mobility of potassium in soil, and 4) molecular breeding new varieties with greater potassium efficiency through marker assisted selection which will require identification and utilization of potassium associated quantitative trait loci.

• 한국환경보건학회지
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• 제29권1호
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• pp.34-42
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• 2003

The objective of this study is to investigate the waste recycling possibility, practicability, economic efficiency and acid gas sorbent use of the hard-shelled mussel. This study is to investigate the hydration/calcination reaction and fixed bed reactor. The physical-chemical characteristics of the hard-shelled mussel were analyzed by ICP SEM-EDX, BET and pore volume. Thus, the results could be summarized as follows; Hard-shelled mussel can be used as iron-manufacture and chemical sorbents considering more than 53.7% of the mussel is lime content. The SO$_2$removal efficiency of the hard-shelled mussel after calcined hydration increased thirty times as a result of the higher pore size, specific surface area and pore volume. Also, the CaO content, pore volume, pore size distribution and specific surface area greatly influenced the SO$_2$ and NOx removal reactivity. The optimum particle diameter average of hard-shelled mussel was $\pm$100 mesh, which was applied to the sorbent on the medium/small scale waste incinerator and flue gas desulfurization processes.

• 한국가구학회지
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• 제28권4호
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• pp.259-267
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• 2017

Furniture should change according to space. Therefore, it is important that the flexibility of the furniture, the functional efficiency, the economical efficiency and the convenience of the furniture of today. These characteristics are also important for seminar tables that are used temporarily by a large number of people. The seminar furniture currently in use has no shielding plate, there are two forms of table and shielding plate folding table. Therefore, in this research, furniture design and product development that can complement the shortcomings of the seminar furniture currently in use were done. Analysis of problems through overseas investigation and domestic market research, design planning and design, and prototyping. We have sought to optimize the volume by applying the characteristics of RTA furniture to develop a lightweight, lightweight, lightweight, easy to install and easy to use shielding plate, and open and closed system. Basically developed two types of shielding board seminar table basic shape and Roll Screen type, we expanded the scope of application such as each color and pattern. In order to reduce the weight, we replaced the parts such as anchor bolts and hinges and the shielding plate with Roll Screen and pursued volume optimization. As a result of this research, it is expected that the system of mechanisms such as packaging standardization and damage prevention for weight reduction and volume optimization will contribute to building competitiveness by domestic office prefabricated furniture industry's original technology.

• 한국도로학회논문집
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• 제18권3호
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• pp.109-114
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• 2016

PURPOSES : The demand for extending national highways is increasing, but traffic monitoring is hindered because of resource limitations. Hence, this study classified highway segments into 5 types to improve the efficiency of short-term traffic count planning. METHODS : The traffic volume trends of 880 highway segments were classified through R-squared and linear regression analyses; the steadiness of traffic volume trends was evaluated through coefficient of variance (COV), and the normality of the data were determined through the Shapiro-Wilk W-test. RESULTS : Of the 880 segments, 574 segments had relatively low COV and were classified as type 1 segments, and 123 and 64 segments with increasing and decreasing traffic volume trends were classified as type 2 and type 3 segments, respectively; 80 segments that failed the normality test were classified as type 4, and the remaining 39 were classified as type 5 segments. CONCLUSIONS : A theoretical basis for biennial count planning was established. Biennial count is recommended for types 1~4 because their mean absolute percentage errors (MAPEs) are approximately 10%. For type 5 (MAPE =19.26%), the conventional annual count can be continued. The results of this analysis can reduce the traffic monitoring budget.

• 한국환경보건학회지
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• 제32권2호
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• pp.179-185
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• 2006

Effect of organic loading rate on UASB performance was evaluated under the renditions of some surface area/reactor volume ratio and different reactor diameter. At the low leading rate of 0.4 kg $COD/m^3{\cdot}d$, reactor performance was not affected by reactor diameter. At the organic loading rate of 6 kg $COD/m^3{\cdot}d$, however, volatile acid accumulation and low COD removal efficiency is observed in reactor having 6.4 cm diameter, while volatile acid is not accumulated at all and high COD removal efficiency is observed in reactor having 3 cm diameter. Such a difference of reactor performance depending on reactor diameter can be explained that sludge bed can be fluidized by evolved gas bubble in narrow reactor, while sludge bed ran not be fluidized by evolved gas bubble only in wide reactor. At a high organic loading rate of 20 kg $COD/m^3{\cdot}d$, it can be judged that there is no relation between reactor configuration and reactor performance because all reactors showed very low COD removal efficiencies regardless of reactor diameter. Narrow and tall type reactor is favorable condition for making sludge bed fluidization at a constant surface area/reactor volume ratio. Thus, it can be judged that reactor configuration and sludge bed fluidization have great influence to reactor performance.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.696-700
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• 2003

$H_2SO_4$과 Citric acid 은 다른 화학물질보다 토양으로부터 $^{137}Cs$의 추출효율이 높았다. 오래 저장된 방사능오염 토양으로부터 $^{137}Cs$ 제거효율을 높이기 위해 동전기방법에 의한 토양복원 실험 시 $H_2SO_4$과 citric acid를 첨가제로 사용했다. 실험 컬럼으로부터 방출된 방출수의 평균속도는 $2.0{\times}10^{-2}$cm/min이고, 10일 동안 방출된 토양폐액의 부피는 3.6 Pore Volume이다. 10일간 컬럼 내의 $^{137}Cs$의 제거효율이 54%이었다. 한편, 개발된 모델에 의해 계산된 잔류농도 예측 값은 실험으로부터 구한 결과와 거의 일치했다.

• 한국산림과학회지
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• 제86권4호
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• pp.450-458
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• 1997

집재기계의 사용시간을 고려하지 않은 작업경비의 비교는, 국내에서와 같이 기계화 작업의 비율이 낮은 경우에서는 적합하지 않다. 기계 및 장비의 활용도를 극대화 시킬 수 있는 작업량은 각 집재기계마다 다르며, 이에 따라 수확 경영규모에 따른 적정 집재기계의 선택이 중요하다. 본 연구에서는 임목수확 기계의 효율적 이용 관리를 위하여, 작업량에 따른 경제적으로 최적의 집재기계 선택방법을 제시하였다. 우리나라의 임업기계화를 추진하는데 있어서, 기계의 이용률을 극대화시킬 수 있는 시업단위는 기계 장비간의 경제적 우위를 비교하는데 반드시 고려할 사항이며, 인건비 상승에 따른 경제성의 변화도 작업시스템의 선정에 있어 함께 고려하여야 할 것이다.

• 설비공학논문집
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• 제24권12호
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• pp.875-880
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• 2012

The field of the large volume heat exchanger for wasted heat recovery ventilation system is being expanded enormously seeing as the fact that the quantity of reducing energies are huge due to the large volume heat exchanger for wasted heat recovery system at large buildings and factories, which consume large amount of energies while it has been arising huge amount of losses in Korea because of the lack of technology. To develop large volume waste heat recovery heat exchanger, rotor type heat exchanger was simulated for the surface corrugation. Based on the simulation results produced $30,000m^3/h$ grade waste heat recovery, heat exchanger was performed for the actual experiment. In addition, performance tests exceed the capacity of a large waste heat recovery heat exchanger performance test methods proposed.