• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.4864-4882
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• 2016

In this work, we consider the optimization problem of minimizing energy consumption for real-time multicast over wireless multi-hop networks. Previously, a distributed primal-dual subgradient algorithm was used for finding a solution to the optimization problem. However, the traditional subgradient algorithms have drawbacks in terms of i) sensitivity to iteration parameters; ii) need for saving previous iteration results for computing the optimization results at the current iteration. To overcome these drawbacks, using a joint network coding and scheduling optimization framework, we propose a novel distributed primal-dual Random Deflected Subgradient (RDS) algorithm for solving the optimization problem. Furthermore, we derive the corresponding recursive formulas for the proposed RDS algorithm, which are useful for practical applications. In comparison with the traditional subgradient algorithms, the illustrated performance results show that the proposed RDS algorithm can achieve an improved optimal solution. Moreover, the proposed algorithm is stable and robust against the choice of parameter values used in the algorithm.

• 태양에너지
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• 제20권1호
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• pp.21-29
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• 2000

본 연구에서는 하루중의 각 시간별로 서로 다른 경사각도별로 수광면에 입사하는 태양에너지의 강도를 실측을 통하여 정량적인 검토와 분석이 가능하도록 측정된 데이터를 기술자료화하고, 각각의 날별로 일사량 강도가 유사한 날들을 그룹화하기 위하여 시간별 일사량 변화에 따른 다항회귀모형을 일별로 산출하고, 각 날별로 서로 비교하기 위해 일별로 산출된 다항회귀모형의 두 그래프사이의 면적을 계산하여 면적의 차가 거의 없는 날들을 일사량 강도가 유사한 날들로 그룹화하는 기법을 개발하여, 월별 또는 전년을 통하여 이들 그룹을 모형별로 제시한다. 또한 다시 이들 모형별로 태양에너지 이용시스템의 효율을 최대화 할 수 있는 시스템 최적경사각도를 제시하여 해당 지역에 적합한 시스템의 최적 설계기준을 제시하고자 한다.

• 한국전자통신학회논문지
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• 제16권2호
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• pp.339-346
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• 2021

본 연구에서는 더 나은 음식 주문 메커니즘을 제공하고 글로벌 고객의 맞춤형 음식 주문에 대한 레시피 성분 비율을 실시간으로 선택할 수 있는 인터페이스를 구현하였다. 각 레시피 재료의 기본 비율을 보여주는 주문 시스템 화면에 선택 메뉴를 배치하여 글로벌 고객에게 적절한 음식을 제공하고, 단순히 음식 메뉴를 선택하고 주문하는 시스템 없이 레시피 그래프를 구성하여 맞춤형 레시피 재료 구성 비율을 제공하는 알고리즘을 연구하였다. 상호 작용을 가능하게 하여 사용자가 음식 메뉴 주문 장치에서 다양한 레시피 재료의 비율 조정을 통해 맞춤형 서비스를 제공한다.

• Nuclear Engineering and Technology
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• 제13권4호
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• pp.207-220
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• 1981

예평형붕괴를 고려한 통계모형 전산코드 STAPES를 써서 NP-237핵분열 단면적을 입사중성자 에너지 20MeV까지 계산하였다. 중성자 방출에 수반되는 분열과정은 3차 복합핵까지 고려하였으며, 이중분열장벽에 관련된 주요 입력변수는 실험값의 최근 동향을 감안, 전 에너지 영역을 통하여 약 l0%의 편차범위 내에서 부합될 수 있도록 조정하였다. 계산결과는 각 에너지에 대응하는 단면적 값의 표와, 실험값과의 비교를 제시하는 그림으로 나타냈다.

• Asia pacific journal of information systems
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• 제29권4호
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• pp.838-855
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• 2019

Online product reviews are a vital source for companies in that they contain consumers' opinions of products. The earlier methods of opinion mining, which involve drawing semantic information from text, have been mostly applied in one dimension. This is not sufficient in itself to elicit reviewers' comprehensive views on products. In this paper, we propose a novel approach in opinion mining by projecting online consumers' reviews in a multidimensional framework to improve review interpretation of products. First of all, we set up a new framework consisting of six dimensions based on a marketing management theory. To calculate the distances of review sentences and each dimension, we embed words in reviews utilizing Google's pre-trained word2vector model. We classified each sentence of the reviews into the respective dimensions of our new framework. After the classification, we measured the sentiment degrees for each sentence. The results were plotted using a radar graph in which the axes are the dimensions of the framework. We tested the strategy on Amazon product reviews of the iPhone and Galaxy smartphone series with a total of around 21,000 sentences. The results showed that the radar graphs visually reflected several issues associated with the products. The proposed method is not for specific product categories. It can be generally applied for opinion mining on reviews of any product category.

• KIEAE Journal
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• 제15권2호
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• pp.19-26
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• 2015

Purpose: Maximizing human comfort in design of medical environments depends immensely on specialized architects particularly critical care design; the study proposes Evidence-Based Design as an apparent analog to Evidence-Based Medicine. Healthcare facility designs are substantially based on the findings of study in an effort to design environments that augment care by improving patient safety and being therapeutic. On SPSS (Statistical Package for Social Science) t-test is applied to simulate two independent variables of PDR (Pre Design-Research) and POE (Post- Occupancy Evaluation). PDR is conducted on relatively new hospital Hallym University Dongtan Sacred Heart Hospital to analyse visibility from researchers' point of view, here the ICU is arranged in I-Shape. POE is applied on Dongguk University Ilsan Hospital to simulate walking on LogWare where two NS are designed based on L- Shape and Seoul St. Mary's Hospital, The Catholic University of Korea where five NS are functional for ICU Intensive Care Unit, Surgical Intensive Care Unit (SICU), Medical Intensive Care Unit (MICU), Critical Care Unit (CCU), Korean Oriental Medical Care Unit which are mostly arranged in U-Shape, and walking pattern is recognized to be in a zigzag path. Method: T-Test is applied on two dependent communication variables: walkability and visibility, with confidence interval of 95%. This study systematically analyses the Nurse Station (NS) typo-morphology, and simulates nurse horizontal circulation, by computing round route visits to patient's bed, then estimating minimum round route on LogWare stop sequence software. The visual connectivity is measured on depth map graphs. Hence the aim is to reduce staff stress and fatigue for better patients care by minimizing staff horizontal travel time and to facilitate nurse walk path and support space distribution by increasing effectiveness in delivering care. Result: Applying visibility graph and isovist field on space syntax on I- Shape, L- Shape and U- Shape ICU (SICU, MICU and CCU) configuration, I-shape facilitated 20% more patients in linear view as they stir to rise from their beds from nurse station compared to U-shape. In conclusion, it was proved that U-Shape supply minimum walking and maximum visibility; and L shape provides just visibility as the nurse is at pivot. I shape provides panoramic view from the Nurse Station but very rigorous walking.

• 대한치과보철학회지
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• 제44권5호
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• pp.526-536
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• 2006

Statement of problem : Use of fiber composite technology as well as development of nonmetal implant prosthesis solved many problems due to metal alloy substructure such as corrosion. toxicity, difficult casting, expensiveness and esthetic limit. After clinical and laboratory test, we could find out that fiber-reinforced composite prostheses have good mechanical properties and FRC can make metal-free implant prostheses successful. Purpose : The purpose of this study is to evaluate the flexural strength of implant fixed prosthesis using fiber reinforced composite. Material and methods : 2-implant fixture were placed in second premolar and second molar area in edentulous mandibular model, and their abutments were placed, and bridge prostheses using gold, PFG, Tescera, and Targis Vectris were fabricated. Tescera was made in 5 different designs with different supplements. Group I was composed by 3 bars with diameter 1.0mm and 5 meshes, 2 bars and 5 meshes for Group II, 1 bar and 5 meshes for Group III, and only 5 meshes were used for Group IV. And Group V is composed by only 3 bars. Resin (Tescera) facing was made to buccal part of pontic of gold bridge. All of gold and PFG bridges were made on one model, 5 Targis Vectris bridges were also made on one model, and 25 Tescera bridges were. made on 3 models. Each bridge was attached to the test model by temporary cement and shallow depression was formed near central fossa of the bridge pontic to let 5 mm metal ball not move. Flexual strength was marked in graph by INSTRON. Results : The results of the study are as follows. The initial crack strength was the highest on PFG. and in order of gold bridge Tescera I, Tescera II, Targis vectris, Tescera IV, Tescera III, and Tescera V. The maximum strength was the highest on gold bridge, and in order of PFG, Tescera I, Tescera IV Tescera II, Targis vectris, Tescera III, and Tescera V. Conculsions : The following conclusions were drawn from the results of this study. 1. Flextural strength of implant prosthesis using fiber reinforced composite was higher than average posterior occlusal force. 2. In initial crack strength, Tescera I was stronger than Tescera V, and weaker than PFG. 3. Kinds and number of auxillary components had an effect on maximum strength, and maximum strength was increased as number of auxillary components increased. 4 Maximum strength of Tescera I was higher than Targis vectris, and lower than PFG.

• 상하수도학회지
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• 제25권3호
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• pp.407-417
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• 2011

Nowadays, the high land use, mainly used for urbanization, is affecting runoff loads of non-point pollutants to increase. According to this fact, increasing runoff loads seems like to appear that it contributes to high ratio of pollution loads in the whole the pollution loads and that this non-point source is the main cause of water becoming worse quality. Especially, concentrated pollutants on the impermeable roads run off to the public water bodies. Also the coefficient of runoff from roads is high with a fast velocity of runoff, which ends up with consequence that a lot of pollutants runoff happens when it is raining. Therefore it is very important project to evaluate the quantity of pollutant loads. In this study, I computed the pollutant loadings depending on time and rainfall to analyze characteristics of runoff while first flush storm water and evaluated the runoff time while first flush storm water and rainfall based on the change in curves on the graph. I also computed contribution ratio to identify its impact on water quality of stream. I realized that the management and treatment of first flush storm water effluents is very important for the management of road's non-point source pollutants because runoff loads of non-point source pollution are over the 80% of whole loads of stream. Also according to the evaluation of runoff loads of first flush storm water for SS, run off time was shown under the 30 minute and rainfall was shown under the 5mm which is less than 20% of whole rainfall. These are under 5mm which is regarded amount of first flush storm water by the Ministry of Environment and it is judged to be because run off by rainfall is very fast on impermeable roads. Also, run off time and rainfall of BOD is higher than SS. Therefore I realized that the management of non-point source should be managed and done differently depending on each material. Finally, the contribution ratio of pollutants loads by rainfall-runoff was shown SS 12.7%, BOD 12.7%, COD 15.9%, T-N 4.9%, T-P 8.9%, however, the pollutants loads flowing into the steam was shown 4.4%. This represents that the concentration of non-point pollutants is relatively higher and we should find the methodical management and should be concerned about non-point source for improvement on water quality of streams.

• 한국가스학회지
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• 제2권2호
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• pp.18-25
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• 1998

천연가스 배관에서 배관 두께는 ANSI B3l.8의 요건에 따라 내압에서 발생하는 원주방향응력으로부터 계산된다. 이외에도 매설배관에는 토양, 차량, 열팽창, 지반침하등도 작용되는데 이에 대한 평가가 필요하다. 매설가스배관에 걸리는 응력을 계산하는데는 두 가지방법이 있다. 첫째는 유한요소법(FEM)으로 배관형상이나 경계조건의 복잡함에 관계없이 응력을 계산할 수 있으나, 많은 비용과 시간이 걸린다. 두 번째는 수식을 이용하는 방법으로 매설가스배관의 응력을 계산하는 적절한 수식을 개발하여 배관설계와 안전성평가에 사용하고 있으나, 비전문가가 사용하고 이해하기에는 어려운 면이 많다. 본 연구에서는 여러 외부인자들이 매설 천연가스배관의 응력에 미치는 영향을 파악하기 위해 응력해석 비전문가가 쉽게 사용이 가능한 컴퓨터 프로그램을 개발하고자 하였다. 응력은 수식과 FEM에서 유도된 그래프에서 유추한 값으로 계산하였다. 전체논문은 두편으로, 본 논문에서는 우선 프로그램에 사용된 수식을 설명하였다.

• 한국전산유체공학회지
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• 제20권3호
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• pp.35-40
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• 2015

Centrifugal pumps consume considerable amounts of energy in various industrial applications. Therefore, improving the efficiency of pumps machine is a crucial challenge in industrial world. This paper presents numerical investigation of flow characteristics in volutes of centrifugal pumps in order to compare the energy consumption. A wide range of volumetric flow rate has been investigated for each case. The standard k-${\varepsilon}$ is adopted as the turbulence model. The impeller rotation is simulated employing the Multi Reference Frames(MRF) method. First, two different conventional design methods, i.e., the constant angular momentum(CAM) and the constant mean velocity (CMV) are studied and compared to a baseline volute model. The CAM volute profile is a logarithmic spiral. The CMV volute profile shape is an Archimedes spiral curve. The modified volute models show lower head value than baseline volute model, but in case of efficiency graph, CAM curve has higher values than others. Finally for this part, CAM curve is selected to be used in the simulation of different cross-section shape. Two different types of cross-section are generated. One is a simple rectangular shape, and the other one is fan shape. In terms of different cross-section shape, simple rectangular geometry generated higher head and efficiency. Overall, simulation results showed that the volute designed using constant angular momentum(CAM) method has higher characteristic performances than one by CMV volute.