• Communications for Statistical Applications and Methods
• /
• v.24 no.2
• /
• pp.129-142
• /
• 2017

In this paper we consider the problem of the model selection/discrimination among three different positively skewed lifetime distributions. Lindley, Weibull, and gamma distributions have been used to effectively analyze positively skewed lifetime data. This paper assesses how much closer the Lindley distribution gets to Weibull and gamma distributions. We consider three techniques that involve the likelihood ratio test, asymptotic likelihood ratio test, and minimum Kolmogorov distance as optimality criteria to diagnose the appropriate fitting model among the three distributions for a given data set. Monte Carlo simulation study is performed for computing the probability of correct selection based on the considered optimality criteria among these families of distributions for various choices of sample sizes and shape parameters. It is observed that overall, the Lindley distribution is closer to Weibull distribution in the sense of likelihood ratio and Kolmogorov criteria. A real data set is presented and analyzed for illustrative purposes.

• Proceedings of the KSR Conference
• /
• 2002.05a
• /
• pp.597-602
• /
• 2002

This study reviews several of the procedures that have been used to predict ground-born vibration. The vibration responses are measured at three sites that have different soil qualities. The measured vibration levels are compared with the predicted results by previously used vibration level prediction models. In this study a numerical method, which is based on explicit differential method, is used to compensate tot existing prediction models. Although numerically computed results are not quantitatively in good agreement with the measured results, the trends are comparable in the sense that vibration level does not decrease monotonically with distance. Also, The site with the deepest tunnel gives the highest vibration level.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.12
• /
• pp.1207-1212
• /
• 2007

We propose a haptic interface algorithm for joystick operators working in remote control systems of unmanned vehicles. The haptic interface algorithm is implemented using a force-feedback joystick, which is equipped with low price DC motors without encoders. Generating specific amounts of forces on the joystick pole according to the distance between a remote controlled vehicle and obstacles, the haptic interface enables the operator to perceive the distance information by the sense of touch. For the case of no joystick operation or no obstacles in the working area, we propose an origin control algorithm, which positions the joystick pole at the origin. The origin control algorithm prevents the false movement of the remote vehicles and provides the operator with a realistic force resisting the joystick pole's movement. The experiment results obtained under various scenarios exemplify the validity of the proposed haptic interface algorithm and the origin control algorithm.

• Journal of Korea Society of Industrial Information Systems
• /
• v.5 no.2
• /
• pp.56-61
• /
• 2000

The quality of English to Korean Machine Translation depends on how well it deals with target word selection of verbs containing enormous ambiguity. Verb sense disambiguation can be done by using collocation, but the construction of verb collocations costs a lot of efforts and expenses. So, existing methods should be examined in the practical view points. This paper describes the practical method of target word selection using existing collocation and semantic distance computed from minimum semantic features of nouns.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.10
• /
• pp.1176-1178
• /
• 2016

We propose some binary locally repairable codes with locality 2 uising a parity-check matrix. The minimum distance of the proposed codes is 6. The proposed codes are optimal in the sense of achieving the upper bound of dimension for given length, minimum distance, and locality.

• International Journal of Highway Engineering
• /
• v.15 no.1
• /
• pp.47-56
• /
• 2013

PURPOSES: This study is to evaluate a ground water level effect on frost heaving in road pavements. METHODS: The effects of water table on frost heaving in pavement systems were evaluated from the mechanical analysis using FROST program. The input parameters and boundary conditions were determined by considering climates, pavement sections, and material properties specially subgrade soil types in Korea. RESULTS: When the water table located above the freezing depth, amount of frost heaving caused by freezing the water in pavement itself was big enough to damage in pavement system, although pavement system consists of fully non-frost-susceptible materials with sufficient thickness of anti-freezing layer. The amount of frost heaving was decreased rapidly with increasing the distance between the water table and freezing depth. CONCLUSIONS: It was concluded that there is no engineering problems related with frost heaving in practical sense when the distance between freezing depth and water table is over 1.5m for having subgrade soils less than 50% of #200 sieve passing to meet specification on quality control in Korea.

• Journal of KSNVE
• /
• v.7 no.3
• /
• pp.419-426
• /
• 1997

The psychological, physiological, and material effects of ground vibrations induced from railroad were surveyed with the magnitudes of vibration sensing using questionnaire on residents living near railroad. These magnitude of vibration sensing and effects were compared as rate or percent total based on double distances from railraod. Also overall effects of railraod vibrations were compared with vibration levels measured or predicted. The about 70% of residents living within 40m from railroad sense railroad vibration, 15% of residents are influenced phychologically. But physilogical and material effects disappeared beyond 40m.

• Proceedings of the IEEK Conference
• /
• 2002.06e
• /
• pp.29-32
• /
• 2002

In this paper the wheeled mobile robot is studied. The kinematic and dynamic modeling of the robot is presented via LPD(Linear Parameter Dependent) framework. A path-planning algorithm which is optimized in the sense of robot mobility and distance is presented. And by using PI controller we show that the presented algorithm and model is work very well in the computer simulation and experiment.

• Journal of applied mathematics & informatics
• /
• v.7 no.3
• /
• pp.983-994
• /
• 2000

We consider the problem of determining the circle of best fit to a set of data points in the plane. In [1] and [2] several algorithms already have been given for fitting a circle in least squares sense of minimizing the geometric distances to the given data points. In this paper we present another new descent algorithm which computes a parametric represented circle in order to minimize the sum of the squares of the distances to the given points. For any choice of starting values our algorithm has the advantage of ensuring convergence to a local minimum. Numerical examples are given.

• Journal of applied mathematics & informatics
• /
• v.29 no.3_4
• /
• pp.713-719
• /
• 2011

The problem of approximation from a set of scattered data arises in a wide range of applied mathematics and scientific applications. In this study, we present a quasi-interpolatory approximation scheme for scattered data approximation problem, which reproduces a certain space of polynomials. The proposed scheme is local in the sense that for an evaluation point, the contribution of a data value to the approximating value is decreasing rapidly as the distance between two data points is increasing.