• Korean Journal of Mathematics
• /
• 제27권1호
• /
• pp.119-129
• /
• 2019

Balance function is one of the joint factors to determine fall in risk theory. It helps to moderate the progression and riskiness of falls for detecting balance and fall risk factors. Nevertheless, the objective measures for balance function require expensive equipment with the assessment of any expertise. We establish the existence and uniqueness of a multi-order fractional differential equations based on ${\psi}$-Hilfer operator on time scales with balance function. This class describes the dynamic of time scales derivative. Our tool is based on the Schauder fixed point theorem. Here, sufficient conditions for Ulam-stability are given.

• 한국항공우주학회지
• /
• 제47권7호
• /
• pp.535-540
• /
• 2019

MDO(Multi-disciplinary Optimization)를 위한 서로 다른 모델 간의 결합은 계산 프레임 워크의 복잡성을 크게 증가시키는 동시에 CPU 시간과 메모리 사용을 증가시킨다. 이러한 어려움을 극복하기 위해 POD(Proper Orthogonal Decomposition)와 RBF(Radial Basis Function)를 사용하여 복합 샌드위치 구조가 항공기 날개 스킨 재료로 사용될 때 복합재와 샌드위치 코어의 두께를 결정하는 최적화 문제의 해를 구했다. POD와 RBF를 사용하여 날개 형상과 하중 데이터에 대한 대리 모델을 만들었으며 대리 모델에 의해 얻어진 목적 함수 및 제약 함수 값을 사용하여 최적해를 구하였다.

• International Journal of Precision Engineering and Manufacturing
• /
• 제8권4호
• /
• pp.10-15
• /
• 2007

Taguchi methods have been used for a long time to improve the product quality and process performance of a manufacturing system, Few researchers have applied this methodology in laser beam cutting (LBC) of sheet metals and found the considerable improvement in cut qualities. In all experimental investigations of LBC so far, the objective was to optimize the single quality characteristic at a time. In this paper the simultaneous optimization of multiple quality characteristics such as Kerf width and material removal rate (MRR) during pulsed Nd:YAG LBC of thin sheet of magnetic material (high Silicon-steel) has been presented using Taguchi's quality loss function. The results show the considerable improvement in multiple S/N ratio as compared to initial cutting condition. Also, the comparison of results from single and multi-objective optimization have been presented and it was found that the loss in quality is always possible shifting from single quality to multiple quality optimization.

• 한국해양공학회지
• /
• 제23권3호
• /
• pp.1-5
• /
• 2009

It is necessary to develop an efficient optimization technique to optimize engineering structures that have given design spaces, discrete design values, and several design goals. In this study, an optimum algorithm based on the genetic algorithm was applied to the multi-object problem to obtain an optimum solution that simultaneously minimizes the structural weight and construction cost of panel blocks in ship structures. The cost model was used in this study, which includes the cost of adjusting the weld-induced deformation and applying the deformation control methods, in addition to the cost of the material and the welding cost usually included in the normal cost model. By using the proposed cost model, more realistic optimum design results can be expected.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
• /
• pp.200-202
• /
• 1999

This paper describes the optimization problem of real power rescheduling and present an algorithm based linear programming for studying the load-shedding and generation reallocation problem when a portion of the transmission system is disabled and at power flow solution cannot be obtained for the overload of some lines. And in case initial is infeasible, solution could not be converge. So this paper gives an algorithm being lie infeasible quantities within limit. The paper describes a LP-based algorithm to obtain the solution in power dispatch related to overload situations in power system and it is easily extened under various objective. The optimization procedures is based in linear programming with bounded variables and use the multi-segment curve method for a objective function and the validity of the algorithm is verified with two examples : 10-bus system and 57-bus system.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.138-139
• /
• 2007

This research provides machine designers with some intuition to consider both, magnetic and heat transfer effects. A topological multi-objective function includes magnetic energy and heat inflow rate to the system, which equals to the total heat dissipation by conduction and convection. For the thermal field regarding the heat inflow, introduced as a reaction force, topology design sensitivity is derived by employing discrete equations. The adjoint variable method is used to avoid numerous sensitivity evaluations. As a numerical example, a C-core design excited by winding current demonstrates the strength of the multi-physical approach.

• International Journal of Computer Science & Network Security
• /
• 제23권8호
• /
• pp.159-167
• /
• 2023

Objective: • To detect black hole and warm hole attacks in wireless sensor networks. • To give a solution for energy depletion and security breach in wireless sensor networks. • To address the security problem using strategic decision support system. Methods: The proposed stackelberg game is used to make the spirited relations between multi leaders and multi followers. In this game, all cluster heads are acts as leaders, whereas agent nodes are acts as followers. The game is initially modeled as Quadratic Programming and also use backtracking search optimization algorithm for getting threshold value to determine the optimal strategies of both defender and attacker. Findings: To find optimal payoffs of multi leaders and multi followers are based on their utility functions. The attacks are easily detected based on some defined rules and optimum results of the game. Finally, the simulations are executed in matlab and the impacts of detection of black hole and warm hole attacks are also presented in this paper. Novelty: The novelty of this study is to considering the stackelberg game with backtracking search optimization algorithm (BSOA). BSOA is based on iterative process which tries to minimize the objective function. Thus we obtain the better optimization results than the earlier approaches.

• 한국지반공학회논문집
• /
• 제25권9호
• /
• pp.93-100
• /
• 2009

본 연구에서 역해석에 이용한 직접법은 실제 변위와 목적함수의 차이를 최소화하고 미지변수를 보정하는 최적화가 핵심 과정이다. 연구과정이 복수의 지층을 단계별로 역해석하여 각 지반의 미지변수를 역해석하기 때문에 지층 간 미지변수의 간섭 효과를 최소화 할 수 있는 추가적인 최적화가 필요하다. 따라서 효율적이고 정확한 최적화를 위해서 목적함수의 편미분 계산과정이 없이 최적해를 구할 수 있는 직접탐색법(direct search method)을 사용하였다. 본 연구의 목적은 지하구조체가 포함된 지층을 상부와 하부의 지층으로 모형화하고, 다중 미지변수를 역해석하는 기법을 개발하는 데에 목적을 둔다. 또한 단계별 역해석된 미지변수의 상호 간섭 오차를 최소화하기 위해서 반복 역해석을 실시하고, 실제 존재하는 터널에 대하여 적용성에 대해 검토하였다. 그 결과, 단층 모형화보다 다층 모형화 결과가 실제 지하구조물거동을 정확히 나타냈으며 다층 경계부에 위치한 지하구조물의 다층지반 모형화를 통한 역해석이 유효함을 확인하였다.

• 전기학회논문지
• /
• 제57권3호
• /
• pp.369-374
• /
• 2008

This paper presents the evaluation procedures and the estimation method for the estimation of optimal rebate level for EE(Energy Efficiency) programs. The penetration amount of each appliance is estimated by applying price function to preferred diffusion model resulted from model compatibility test. To estimate the optimal rebate level, two objective functions which express the maximum energy saving and operation benefit are introduced and by multi-objective function which can simultaneously consider two objective functions the optimal rebate level of each appliance is estimated. And then, using the decided rebate level and each penetration amount, the priority order for reasonable investment of each high-efficiency appliance is estimated compared to the results of conventional method. Finally, using a benefit/cost analysis based on California standard practice manual, the economic analysis is implemented for the four perspectives such as participant, ratepayer impact measure, program administrator cost and total resource cost.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.869-874
• /
• 2005

This paper proposes the Pareto artificial life algorithm for a multi-objective function optimization problem. The artificial life algorithm for a single objective function optimization problem is improved through incorporating the new method to estimate the fitness value fur a solution and the Pareto list to memorize and to improve the Pareto optimal set. The proposed algorithm is applied to the optimum design of a Journal bearing which has two objective functions. The Pareto front and the optimal solution set for the application are reported to present the possible solutions to a decision maker or a designer.