• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.514-518
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• 2003

In this paper, we investigate three dimensional optimal evasive maneuver patterns for air-to-surface attack missiles against proportionally navigated anti-air defense missiles. Interception error of the defense missile can be generated by evasive maneuver of the attack missile during the time of flight for which the defense missile intercepts the attack missile. Time varying weighted sum of the inverse of these interception errors forms a performance index to be minimized. Direct parameter optimization technique using CFSQP is adopted to get the attack missile's optimal evasive maneuver patterns according to parameter changes of both the attack missile and the defense missile such as maneuver limit and time constant of autopilot approximated by the 1st order lag system. The overall shape of resultant optimal evasive maneuver to enhance the survivability of air-to-surface missiles against proportionally navigated anti-air missiles is a kind of deformed barrel roll.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.22 no.1
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• pp.1-13
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• 2018

Boosting, one of the most successful algorithms for supervised learning, searches the most accurate weighted sum of weak classifiers. The search corresponds to a convex programming with non-negativity and affine constraint. In this article, we propose a novel Conjugate Gradient algorithm with the Modified Polak-Ribiera-Polyak conjugate direction. The convergence of the algorithm is proved and we report its successful applications to boosting.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.376-379
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• 2007

In recent years, the natural damage associated with flood disaster has been dramatically increased. However, there is no rational method which reflects urban characteristics to estimate the regional safety assessment for flood disaster. The purpose of this study is to develop the regional safety assesment model for urban flood. Flood risk and reduction assesment were estimated by using the linear sum of the Z score of the assessment factors and the weight value of each factor from the expert survey data. And then the regional safety assessment was estimated by subtracting reduction factor value from risk factor value. GIS tool was used to estimate the factor assesment and integrated regional safety. This study can be used to determine the priority of flood protection project, execute the flood insurance and establish the urban plans and the flood mitigate plan.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.94-97
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• 2005

The strength of aluminum 7075 and carbon composite hybrid joints was studied for adhesive, bolt, and the adhesive-bolt combined joints. Several hybrid joint specimens were tested to get the failure load and modes for three types of the joints. Adhesive Cytec EA9394S was used for aluminum and carbon bonding. Failure load of the adhesive-bolt combined joint was 94 % of the sum of the failure load of the separately bonded and bolted joints. Hybrid joint also showed more stable failure behavior than the simple adhesive or bolted joint.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1353-1357
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• 2005

하천에서의 보다 정확한 수질변화의 예측과 하천관리를 위해서는 수질관측지점에 대한 지속적인 수문관측을 병행함으로써 하천흐름에 대한 물리적인 특성의 이해가 수반되어야 할 것이다. 본 연구에서는 횡성댐 상류에 위치한 계천에 시험유역을 구축하여 하천에서의 흐름변화와 수질변화를 동시에 실시간으로 감시할 수 있는 수문$\cdot$수질관측시스템과 하천에서의 수질오염사고에 대비한 하류부의 수질변화를 모의할 수 있는 수질모의시스템을 구축하였으며, 실제 관측한 수질자료를 이용한 모형의 보정을 실시하여 적용성을 검토하였다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.179-187
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• 2005

In this paper, we consider the problem of regrouping a number of service sites into a smaller number of service sites called centers. Each service site is represented as a point in the plane and has an associated value of service demand. We aim to group the sites so that each group has the balanced service demand and the sum of distances from the sites in the group to their corresponding center is minimized. To solve this problem, we propose a hybrid genetic algorithm that is combined with Voronoi diagrams. We provide a variety of experimental results by changing the weights of the two factors: service demands and distances. Our hybrid algorithm finds better solutions in a shorter computation time in comparison with a pure genetic algorithm.

• Journal of the Korean Mathematical Society
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• v.55 no.1
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• pp.185-210
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• 2018

The Hurwitz-type Euler zeta function is defined as a deformation of the Hurwitz zeta function: $${\zeta}_E(s,x)={\sum_{n=0}^{\infty}}{\frac{(-1)^n}{(n+x)^s}}$$. In this paper, by using the method of Fourier expansions, we shall evaluate several integrals with integrands involving Hurwitz-type Euler zeta functions ${\zeta}_E(s,x)$. Furthermore, the relations between the values of a class of the Hurwitz-type (or Lerch-type) Euler zeta functions at rational arguments have also been given.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.265-268
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• 2006

Performed fatigue strength analysis for Hub to get the targeted service life of 20 years. ANSYS is used to analysis. The major structure of bearing which connect the hub and blades is modeled using the element of LINK10. To represent the stiffness of LINK10 element, initial strain and diameter of LINK10 element is applied. Prior to calculating the fatigue damages, the influence matrix is extracted from the unit loads. The target service life of 20 years is achieved from the Analysis results.

• Journal of the Korean Society of Food Culture
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• v.12 no.5
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• pp.567-572
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• 1997

This reserch was carried out to investigate the nitrite scavenging abilities (NSA) of 7 kinds of tea extracts. Nitrites are used as additives of cured meat preperation and exist in plants, foods, and medicines, so we intake it very often easily. Nitrites can act with amines to produce nitrosamine which is known to be a carcinogen. It is known that the pH, concentration of amines, and amounts of nitrite are three important conditions of nitrosamine occurence. 7 kinds of tea used in this experiment were Persimmon tree (Diospyroo kaki Thiunb, Per.), Mulberry tree (Morus alba Linne, Mul.), Rubber tree (eucommia ulmoi-des Oliver, Rub.), Solomon's-seal (Bolygonatu Morr, Som.), Chicory (Cichorrium intybus L, Chi.), Sumach (Rhus javanica L., Sum.), Docwood (Cornus officinale Sieb, Doc.) and they were extracted with methanol (MeOH), ethyl ether (EtEt), ethyl acetate (EtAc), and also the extract existed in the aqueous layer II (Aq L. II) was used.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.99-108
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• 2001

In the ring loading problem with demand splitting, traffic demands are given for each pall of nodes in an undirected ring network and a flow is routed in either of the two directions, clockwise and counter-clockwise. The load of a link is the sum of the flows routed through the link and the objective of the problem is to minimize the maximum load on the ring. The fastest a1gorithm to date is Myung, Kim and Tcha＇s a1gorithm that runs in Ο(n｜K｜) time where n is the number of nodes and K is the index set of the origin-destination pairs of nodes having flow traffic demands. Here we develop an a1gorithm for the ring loading problem with demand splitting that improves the rerouting step of Myung, Kim and Tcha＇s a1gorithm arid runs in Ο(min{n｜K｜, n$^2$}) time.