• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.85-89
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• 2013

In the current domestic, many industrial accidents have happened. And these are analyzed according to several factors. But it is difficult that they evaluate their business safety. Thus, we conducted a study on business specific safety assessment techniques in order that business know their safety level and perform appropriative safety activities. Study methods are survey and AHP (Analytic Hierarchy Process). Each specific weighting factors to calculate the survey was conducted for safety and consulting experts (20 persons). Weight factor was used to AHP decision support as one of the ways through a number of alternatives to the ratings for the Minesota Multiphasic. Factors are each type of industry, specific industrial scale, disaster type and strength, worker age and tenure period, and region. First, survey was conducted with 20 professionals to estimate the weighting factors. Weights between factors using the AHP analysis tool based on the mean values were calculated. Second, last 3 years between the industrial accidents statistics were used to calculate the weights for each of the rating factors in the Occupational Safety and Health Agency. Grade weights between each factor which was based on the rating of each factor was calculated as the average of three years. Finally, the weights between each factor and the grade weights for each factor using the safety level of the enterprise were calculated so that you can evaluate the weighting.

• Structural Engineering and Mechanics
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• v.62 no.2
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• pp.247-258
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• 2017

Beam-like structures such as bridge, high building and tower, pipes, flexible connecting rods and some robotic manipulators are often excited by support motions. These structures are important in machines and structures. So, this study proposes an analytic method to accurately predict the dynamic behaviors of the structures during support motions or an earthquake. Using Timoshenko beam theory which is valid even for non-slender beams and for high-frequency responses, the analytic responses of fixed-fixed beams subjected to a real seismic motions at supports are illustrated to show the principled approach to the proposed method. The responses of a slender beam obtained by using Timoshenko beam theory are compared with the solutions based on Euler-Bernoulli beam theory to validate the correctness of the proposed method. The dynamic analysis for the fixed-fixed beam subjected to support motions gives useful information to develop an understanding of the structural behavior of the beam. The bending moment and the shear force of a slender beam are governed by dynamic components while those of a stocky beam are governed by static components. Especially, the maximal magnitudes of the bending moment and the shear force of the thick beam are proportional to the difference of support displacements and they are influenced by the seismic wave velocity.

• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.37-47
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• 2017

Climate change has often resulted in severe droughts in a rice-farming season (i.e., April to June), and the large amount of water resources were needed to cope with droughts during the season. Therefore, the subsurface dam, which is able to store groundwater resources in the alluvium aquifer, has been considered to be an alternative for securing more groundwater resources. In this study, suitable sites assessment criteria for agricultural subsurface dam using analytic hierarchy process (AHP) were established for adequate drought management. Moreover, the criteria were applied to the existing five agricultural subsurface dams to verify their applicability of groundwater supply for each subsurface dam. The assessment criteria were divided into three major categories (geology, hydrology and business condition) and classified to 12 individual sub-categories with weighting. From the assessment, Ian subsurface dam and Wooil subsurface dam were identified as the best and the worst suitable site, respectively, and this result was in accordance with the average amount of annual groundwater supply by each subsurface dam during the period of 2011-2017.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.2
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• pp.112-120
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• 2021

The novel wave generating system of a wave flume has been devised by utilizing the analytic solution of wave board motion in idealized two dimensional space. The arbitrary oscillation motion of submerged wave board segment has been defined by sinusoidal motion of upper and lower end of the wave board. The analytic solution of the wave board motion has been represented by the solution of board motion due to flap motion and swing motion. Arbitrary oscillation of the board could be specified by determining amplitude, frequency, and the phase lag. A novel hybrid wave generator could be operated not only in piston motion but also in flap or swing motion by selection of control parameter. The wave generator has unique motion enhancing ability by appending flap motion or swing motion to piston motion in wave generation. In addition the hybrid wave generator has advantages in generating high quality wave spectrum of irregular wave in simulating real sea condition.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.11
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• pp.1097-1104
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• 2008

Working condition is one of the most important factors in precision working. In this study, we optimized the vibration acceleration of working progress direction using RSM(response surface methodology) by table of orthogonal array. RSM was well adapted to make analytic model for minimizing vibration acceleration, created the objective function and saved a great deal of computational time. Therefore, it is expected that the proposed optimization procedure using RSM can be easily utilized to solve the optimization problem of working condition. The experimental results of the surface roughness and vibration acceleration showed the validity of the proposed working condition of side wall end-milling as it can be observed.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.423-439
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• 2006

This paper proposes a hybrid analytic method for the prediction of vibrational and acoustic responses of reverberant system in the medium-to-high frequency ranges by using the PFA(Power Flow Analysis) algorithm and SEA(Statistical Energy Analysis) coupling concepts. The main part of this method is the application of the coupling loss factor(CLF) of SEA to the boundary condition of PFA in reverberant system. The hybrid method developed shows much more promising results than the conventional SEA and equivalent results to the classical PFA for various damping loss factors in a wide range of frequencies. Additionally, this paper presents applied results of hybrid power flow finite element method(hybrid PFFEM) by formulating the new joint element matrix with CLF to analyze the vibrational responses of built-up structures. Finally, the analytic results of coupled plate structures and an automobile-shaped structure using hybrid PFFEM were predicted successively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.9
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• pp.2329-2338
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• 1993

An accurate analysis procedure to solve the flow about a flat plate at various incidences has been developed. The Navier-Stokes equations of stream function and vorticity form are solved in a sufficiently large computational domain, in which the grid lines are mutually orthogonal. The details of the flow near the singularity at the tip of the plate is well captured by the analytic solution which is asymptotically matched to the numerically generated outer solution. The solution for each region is obtained iteratively : the solution of one (inner or outer) region uses that of the other as the boundary condition after each cycle. The resulting procedure is accurate everywhere and also computationally efficient as the singularity has been removed. It is applied to the flat plate for a wide range of Re : the results agree very well with the existing computation and experiment.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.94-100
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• 2010

Nowadays, several nontraditional machining(NTM) processes are widely used to machine a complex and accurate shape part of hard materials, such as titanium, ceramics, high strength temperature resistant and refractory materials which are difficult to machine and having high strength, hardness, toughness. Machining of these complex shapes in such materials by traditional machining processes are very difficult. The NTM processes is important in the areas of micro- and nano scale machining, where high accuracy and superior surface characteristics are required, which can only be achieved using these NTM processes. So, for effective selection of different NTM processes, careful decision making for a given NTM application is often necessary. An appropriate NTM process for a given material and shape condition is very difficult for the novice engineers. In this paper, an expert system based on an analytic network process(ANP) is suggested for a best selection of NTM process in a NTM application considering an prior interdependency effect among various factors.

• Journal of applied mathematics & informatics
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• v.33 no.5_6
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• pp.699-721
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• 2015

This paper investigates the existence of mild solution for a fractional integro-differential equations with a deviating argument and nonlocal initial condition in an arbitrary separable Hilbert space H via technique of approximations. We obtain an associated integral equation and then consider a sequence of approximate integral equations obtained by the projection of considered associated nonlocal fractional integral equation onto finite dimensional space. The existence and uniqueness of solutions to each approximate integral equation is obtained by virtue of the analytic semigroup theory via Banach fixed point theorem. Next we demonstrate the convergence of the solutions of the approximate integral equations to the solution of the associated integral equation. We consider the Faedo-Galerkin approximation of the solution and demonstrate some convergenceresults. An example is also given to illustrate the abstract theory.

• Communications of the Korean Mathematical Society
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• v.18 no.3
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• pp.469-479
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• 2003

Let B be the open unit ball in $C^{n}$ and ${\mu}_{q}$(q > -1) the Lebesgue measure such that ${\mu}_{q}$(B) ＝ 1. Let ${L_{a,q}}^2$ be the subspace of ${L^2(B,D{\mu}_q)$ consisting of analytic functions, and let $\overline{{L_{a,q}}^2}$ be the subspace of ${L^2(B,D{\mu}_q)$) consisting of conjugate analytic functions. Let $\bar{P}$ be the orthogonal projection from ${L^2(B,D{\mu}_q)$ into $\overline{{L_{a,q}}^2}$. The little Hankel operator ${h_{\varphi}}^{q}\;:\;{L_{a,q}}^2\;{\rightarrow}\;{\overline}{{L_{a,q}}^2}$ is defined by ${h_{\varphi}}^{q}(\cdot)\;=\;{\bar{P}}({\varphi}{\cdot})$. In this paper, we will find the necessary and sufficient condition that the little Hankel operator ${h_{\varphi}}^{q}$ is bounded(or compact).