디지털 레버리징: 기술을 인간의 삶에 적용하는 방법론

한석영,김희철,황원주 한국멀티미디어학회 2019 멀티미디어학회논문지 Vol.22 No.2

After the launch of smart phones, various miniaturized smart devices such as wearable and IOT devices have deeply embedded in human life, and have created a technology-oriented society. In this technologyoriented society, technology development itself is important, however it seems more important to utilize existing technology appropriately and deliver effectively to human life. As the computer became personalized after the appearance of PC, human-centered computing such as HCI and UCD had begun to appear. However, most of the researches focused on technology that made human being convenient to interact with computer such as computer systems design and UX development. In the technology-oriented society, it seems more urgent to apply existing technology to human life. In this paper, we propose a methodology, ‘Digital Leveraging’ which guides how to effectively apply technology to human life. Digital Leveraging is the way of convergence between technology and humanities.

밀도분포법을 이용한 부재의 연결구조 최적화

한석영,유재원 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.4

Most engineering products contain more than one component. Failure occurs either at the connection itself or in the component at the point of attachment of the connection in many engineering structures. The allocation and design of connections such as bolts, spot-welds, adhesive etc. usually play an important role in the structure of multi-components. Topology optimization of connection component provides more practical solutions in design of multi-component connection system. In this study, a topology optimization based on density distribution approach has been applied to optimal location of fasteners such as T-shape, L-shape and multi-component system. From the results, it was verified that the number of iteration was reduced, and the optimal topology was obtained very similarly comparing with ESO method. Therefore, it can be concluded that the density distribution method is very suitable for topology optimization of multi-component structures.

솔리드 요소를 이용한 적층복합재 구멍의 형상 최적화

한석영,마영준 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.4

Shape optimization was performed to obtain the precise shape of cutouts including the internal shape of cutouts in laminated composite plates by three dimensional modeling using solid element. The volume control of the growth- strain method was implemented and the distributed parameter chosen as Tsai-Hill fracture index for shape optimization. The volume control of the growth-strain method makes Tsai-Hill failure index at each element uniform in laminated composites under the initial volume. Then shapes optimized by Tsai-Hill failure index were compared with those of the initial shapes for the various load conditions and cutouts. The following conclusions were obtained in this study (1) It was found that growth-strain method was applied efficiently to shape optimization of three dimensional cutouts in a laminated composite plate, (2) The optimal shapes on the various load conditions and cutouts were obtained, (3) The maximum Tsai-Hill failure index was reduced up to 67% when shape optimization was performed under the initial volume by volume control of growth-strain method.

신경망 최적화 기법을 이용한 다익 홴/스크롤 시스템의 설부에 대한 형상 최적화

한석영,맹주성,유달현,진경욱,Han, Seog-Young,Maeng, Joo-Sung,Yoo, Dal-Hyun,Jin, Kyong-Uk 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.10

In order to improve efficiency of a system with three-dimensional flow characteristics, this paper presents a new method that overcomes three-dimensional effects by using two-dimensional CFD and neural network. The method was applied to shape optimization of cut-off in a multi-blade fan/scroll system. As the entrance conditions of two-dimensional CFD, the experimental values at the positions out of the inactive zone were used. The distributions of velocity and pressure obtained by two-dimensional CFD were compared with those of three-dimensional CFD and experimental results. It was found that the distributions of velocity and pressure have qualitative similarity. The results of two-dimensional CFD were used for teaming as target values of neural network. The optimal angle and radius of cut-off were determined as 71$^{\circ}$and 0.092 times the outer diameter of impeller, respectively. It is quantified in the previous report that the optimal angle and radius of cut-off are approximately 72$^{\circ}$and 0.08 times the outer diameter of impeller, respectively.

황산스트렙토마이신 근육주사시 혼합용매가 조직손상과 동통에 미치는 영향

한석영,오상은 전남대학교 간호과학연구소 2000 Nursing and Health Issues(NHI) Vol.5 No.1

Streptomycin sulfate is an anti-tuberculous agent, which can be injected intra muscularly. With the increased frequency of its injection, the complication such as pain, discomfort, and damage in nerves, vessels, and iocal tissues is on the rise. In particular, local tissue damage of injection site gives a discomfort continuously to patients by fibrosis, necrosis, delayed healing of the tissue, and decreased absorption of the drug. Eventually the recovery and healing process is delayed. The purpose of this study is to compare tissue damage and pain between when streptomycin is injected in normal saline and when injected in distilled water. Also, correlations between damage and pain in terms of gender, age, walking amount, and total body fat after injection have been explored. The subjects of this study were 13 patients who had been diagnosed of pulmonary tuberculosis and hospitalized at K hospital in K wangju from Jan. 3 to Mar. 3, 1999. Streptomycin was injected once a day on each gluteal area of the subjects alternately. After 12 injections tissue damage and pain on the injected area with streptomycin dissolved in saline were compared to those in distilled water as control. The degree of tissue damage and pain after streptomycin injection were measured by needle EMG and self-reported graphic rating scale. The collected data were analysed by SPSS program. The differences of tissue damage and pain between experimental group and control group were analysed by non-parametric Wilcoxon signed rank test. And pain intensities were shown using Box-Plot. Also, correlations between tissue damage and pain in terms of age, total body fat, and walking amount after injection were analysed by Spearman‘s rho correlation coefficient. The difference of tissue damage and pain according to gender was analysed by non-parametric Wilcoxon rank sum test The results of this study were summarized as follows; 1. Needle EMG showed that the muscle tissue of experimental group with normal saline less damaged than that of control group with distilled water(Z=-3.464, p= .001). 2. No significant difference was noted in the degree of pain between experimental group and control group(Z=-.312, p=.755). 3. In the variables of age, total body fat, and walking amount after injection, the tissue damage was correlated with age positively( γ =.516, p=.000). 4. In the variables of age, total body fat, and walking amount after injection, the pain was correlated with walking amount in both groups(normal saline: r =-.328 , p=.003 ; distilled water : r =-.271 , p=.016). 5. No significant difference were noted in the degree of tissue damage (Z=-1.684, p=.092) and pain (Z=- .416, p=.678) according to gender. In conclusion, it is highly recommended that the use of normal saline as a solvent for streptomycin injection to decrease damage of tissue and to promote healing of tissue.

좌굴 하중을 고려한 프레임 구조물의 최적 설계

한석영,진경욱 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.2

In this paper, the comparison of the first order approximation schemes such as SLP (sequential linear programming), CONLIN (convex linearization), MMA(method of moving asymptotes) and the second order approximation scheme, SQP(sequential quadratic programming) was accomplished for optimization of nonlinear structures. It was found that MMA and SQP are the most efficient methods for optimization. But the number of function call of SQP is much more than that of MMA. Therefore, when it is considered with the expense of computation, MMA is more efficient than SQP. In order to examine the efficiency of MMA for complex optimization problem, it was applied to the helicopter tail boom con-sidering column buckling and local wall buckling constraints. It is concluded that MMA can be a very efficient approxima-tion scheme from simple problems to complex problems.

마이크로 유전자 알고리즘을 이용한 구조 최적설계

한석영,최성만 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

SGA (Single Genetic Algorithm) is a heuristic global optimization method based on the natural characteristics and uses many populations and stochastic rules. Therefore SGA needs many function evaluations and takes much time for convergence. In order to solve the demerits of SGA, μGA(Micro-Genetic Algorithm) has recently been developed. In this study, μGA which have small populations and fast convergence rate, was applied to structural optimization with discrete or integer variables such as 3, 10 and 25 bar trusses. The optimized results of μGA were compared with those of SGA. Solutions of μGA for structural optimization were very similar or superior to those of SGA, and faster convergence rate was obtained. From the results of examples, it is found that μGA is a suitable and very efficient optimization algorithm for structural design.

탠덤압연설비에서 테이퍼롤 채용에 의한 냉연강판 에지드롭 개선

한석영,이준정 대한기계학회 1994 대한기계학회논문집 Vol.18 No.1

In order to improve thickness profile of cold rolled steel strip, a computer simulation and actual cold rolling experiments on a 4-high tandem cold mill were carried out. In this study, tapered barrel end at top work roll and incurved barrel body at bottom work roll were examined for reducing edge drop and threading of stripe. Also, the most effective stand of tandem cold mill and magnitude of optimal taper crown at several stand were investigated under a typical rolling condition. From actual rolling experiments, it was verified that thickness deviation over strip width could be improved up to 1.06% by applying tapered and incurved work roll only at the second and up to 0.89% by applying them at both the second and the third stand.

경험적 최적화 기법을 이용한 자동차 공력저항 예측 프로그램 개발

한석영,맹주성,박재용 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

At present, wind tunnel test or CFD is used for predicting aerodynamic drag coefficient in motor company. But, wind tunnel test requires much cost and time, and CFD has about 30% error. In this study a predicting program of the aerodynamic drag coefficient based on empirical techniques was developed. Also a mathematical optimization method using GRG method was added to the program. The program was applied to six cars. Aerodynamic drag coefficient values of six cars were predicted with 4.857% average error. The optimization method was also applied to six cars. Three parameters selected from sensitivity analysis were determined to reduce the afterbody drag coefficient to the value established by a designer and when some parameters were changed for a developing automotive, optimal modifiable parameters were determined to preserve the same drag coefficient as the original automotive. It was verified that this program could predict the aerodynamic drag coefficient effectively and accurately, and this program with GRG method could determine optimal values of parameters.

체적제어에 의한 적층 복합재 구멍의 형상 최적화

한석영,마영준 대한기계학회 2004 大韓機械學會論文集A Vol.28 No.9