• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권9호
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• pp.4408-4428
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• 2019

Due to the rapid advancement in smart phones, numerous new specifications are developed for variety of applications ranging from health monitoring to navigations and tracking. The word indoor navigation means location identification, however, where GPS signals are not available, accurate indoor localization is a challenging task due to variation in the received signals which directly affect distance estimation process. This paper proposes a hybrid approach which integrates fingerprinting based K-Nearest Neighbors (K-NN) and lateration based MinMax position estimation technique. The novel idea behind this hybrid approach is to use Euclidian distance formulation for distance estimates instead of indoor radio channel modeling which is used to convert the received signal to distance estimates. Due to unpredictable behavior of the received signal, modeling indoor environment for distance estimates is a challenging task which ultimately results in distance estimation error and hence affects position estimation process. Our proposed idea is indoor position estimation technique using Bluetooth enabled smart phones which is independent of the radio channels. Experimental results conclude that, our proposed hybrid approach performs better in terms of mean error compared to Trilateration, MinMax, K-NN, and existing Hybrid approach.

• Management Science and Financial Engineering
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• 제21권1호
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• pp.11-17
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• 2015

Min-max stochastic optimization is an approach to address the distribution ambiguity of the underlying random variable. We present a unified approach to the problem which utilizes the theory of convex order on the random variables. First, we consider a general framework for the problem and give a condition under which the convex order can be utilized to transform the min-max optimization problem into a simple minimization problem. Then extremal distributions are presented for some interesting classes of distributions. Finally, applications to the single-period inventory control problems are given.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.312-315
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• 2003

This paper deals with robust control problems of linear systems with matched nonlinear uncertainties. In order to handle the uncertainties, a Lyapunov min-max control approach can usually be adopted. By the way, the min-max control input is required to be switched and provokes chattering phenomena which limit the practical implementation. The magnitude of switching control input which cause chattering is dependent on the size of uncertainties. In this paper, it is shown that the magnitude of the min-max control input can be made small using a well-known disturbance observer technique and only considers the disturbance observing errors. The chattering phenomena can be reduced as small as possible by selecting a high diturbance observer gain. The simulations show that the min-max control with a disturbance observer can reduce chattering phenomena much smaller and guarantee much better robust performance rather than the one without a disturbance observer.

• Geomechanics and Engineering
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• 제16권4호
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• pp.355-361
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• 2018

In this paper, nonlinear vibration of Euler-Bernoulli beams resting on linear elastic foundation is studied. It has been tried to prepare a semi-analytical solution for whole domain of vibration. Only one iteration lead us to high accurate solution. The effects of linear elastic foundation on the response of the beam vibration are considered and studied. The effects of important parameters on the ratio of nonlinear to linear frequency of the system are studied. The results are compared with numerical solution using Runge-Kutta $4^{th}$ technique. It has been shown that the Max-Min approach can be easily extended in nonlinear partial differential equations.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.781-784
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• 1998

An image segmentation approach based on the fuzzy worm searching and MIN-MAx clusterng algorithm is proposed in this paper. This algorithm deals with fuzzy worm value and min-max node at a gross scene level, which investigates the edge information including fuzzy worm action. But current segmentation methods based edge extraction methods generally need the mask information for the algebraic model, and take long run times at mask operation, wheras the proposed algorithm has single operation ccording to active searching of fuzzy worms. In addition, we also genetic min-max clustering using genetic algorithm to complete clustering and fuzyz searching on grey-histogram of image for the optimum solution, which can automatically determine the size of rnages and has both strong robust and speedy calculation. The simulation results showed that the proposed algorithm adaptively divided the quantized images in histogram region and performed single searching methods, significantly alleviating the increase of the computational load and the memory requirements.

• Structural Engineering and Mechanics
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• 제75권2호
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• pp.239-246
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• 2020

In this paper, a novel analytical method, Max-Min Approach (MMA), has been presented and applied to consider the nonlinear vibration of dry cask storage systems. The nonlinear governing equation of the structure has been developed using the shell theory. The MMA results are compared with numerical solutions derived by Runge-Kutta's Method (RKM). The results indicate a satisfying agreement between MMA and numerical solutions. Parametric studies have been conducted on the nonlinear frequency of dry casks. The phase-plan of the problem is also presented and discussed. The proposed approach can potentially ca be extended to highly nonlinear problems.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.2030-2037
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• 2012

본 연구의 목적은 공업 기술 영어 교과의 교수요목을 설계하기 위한 요구분석의 한 모형을 제안하는 데 있다. 이는 학습자 중심의 교육이 보편화됨에 따라 학습자들의 요구를 학습 내용에 효율적으로 반영하기 위한 방법론을 모색하고자 하는 것이다. 기존의 표준화 점수에 의해 교수요목 순위 선정을 하는 연구에서는 최댓값과 최솟값의 차이가 설문지에서의 Likert 5점 척도보다 크기 때문에 자료를 해석할 때 왜곡될 수 있는 단점을 갖고 있으므로 이에 대한 보완책이 필요하다. 이러한 자료해석의 왜곡을 최소화 해줄 수 있는 방법이 Max-Min 방법이다. 이 논문에서는 기존의 표준화 점수 방법을 이용한 교수요목 선정과 Max-Min 점수 방법에 의한 교수요목 선정의 차이를 밝히고 그 의의를 제시해 본다. 순위 변화율은 기계 금속 관련 항목, 토목 건축 관련, 화공 섬유 관련이 각각 25%, 25%, 55%의 변화율을 보였다. 요구분석은 상황에 맞게 다양하게 선택되어야 하며, 또한 요구분석이 언어 교수요목 설계의 출발점이라고 할 때 이에 대한 정교한 방법론이 필요하다. 따라서 앞으로의 요구분석과 관련한 연구에서는 표준화 방법이나 Max-Min 방법 문제뿐만 아니라 심층연구를 통해서 각 집단의 중요도 차이를 반영할 수 있는 방법론에 대해서도 다각도의 연구가 진행되어 궁극적으로는 요구분석 전반을 아우를 수 있는 방법론 개발이 필요하다.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.375-383
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• 2012

Together with the GPS-based approach, geolocation through mobile communication networks is a key technology for location-based service. Since the Mobile WiMAX system is considered as a candidate for fourth-generation mobile systems, it is important to investigate its location capability. The geolocation of Mobile WiMAX can be realized when the preamble symbols in the down-link channel are appropriately used for a TDOA (Time-Difference-of-Arrival) approach. However, the cellular structure of Mobile WiMAX inevitably generates co-channel interference, and it is difficult for the mobile terminal to acquire distance measurements from multiple base stations. Therefore, for geolocation via multilateration using the Mobile WiMAX network, it is very important to increase hearability. This paper proposes a geolocation method for Mobile WiMAX which employs interference cancellation and preamble signal overlapping for the enhancement of hearability. A novel interference cancellation strategy for complex-valued Mobile WiMAX signals is presented which has an iterative structure. Simulation results show that the proposed geolocation method provides the user's position with an accuracy of less than 20 m through the Mobile WiMAX cellular network if there is no multi-path or NLOS (None-Line-of-Sight).

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1596-1599
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• 2010

Group method of data handling neural networks model (GMDH-NNM) is used to estimate daily pan evaporation (PE) using limited climatic variables such as max temperature ($T_{max}$), min temperature ($T_{min}$), mean wind speed ($W_{mean}$), mean relative humidity ($RH_{mean}$) and sunshine duration (SD). And, for the performances of GMDH-NNM, it is composed of training and test performances, respectively. The training and test performances are carried out using daily time series data, respectively. From this research, we evaluate the impact of GMDH-NNM for the modeling of the nonlinear time series data. We should, thus, construct the credible data of the daily PE data using GMDH-NNM, and can suggest the methodology for the irrigation and drainage networks system. Furthermore, this research represents that the strong nonlinear relationship such as pan evaporation modeling can be generalized using GMDH-NNM.

• 항공우주시스템공학회지
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• 제9권4호
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• pp.31-36
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• 2015

The fatigue analysis for cutout panel used for the weight reduction of aircraft has been conventionally performed through the open hole concept using the reference stress and stress concentration factor (Kt). However, in the actual structure cases, the goal of weight reduction might be less meaningful due to the conservative approach induced by the difficulties of extracting the confident reference stress from FE-Analysis in the complicated loading behavior. Therefore a new approach is proposed in order to secure the effectiveness of weight reduction and validate the confidence of the analysis results using the interaction of max-min principal stress at the critical location of open hole edge line.