• Journal of KSNVE
• /
• v.10 no.2
• /
• pp.299-305
• /
• 2000

In this study, the characteristics of transmitted vibration on hand-arm system are examined when operating electric hand tools. Also through the correlation analysis between anthroponetric data and transmitted vibration, and comparison study with appropriate amount of work done based on the ISO criteriaa, the basic data for the ergonomic work design can be presented. The types of electric tools and works for the experiment are drill (general type and impact type), grinder, wire brush and steel to analyze the characteristics of transmitted vibrations, the amount of transmitted vibrations in X, Y and Z direction at tool(T), hand(H), wrist(W), and the joint between foream and upper arm(A) were measured at the frequency range of 6.3∼1000[HZ]. Also, the limit of human exposure to vibration, and the response of frequency were conducted.

• Journal of KSNVE
• /
• v.8 no.6
• /
• pp.1078-1085
• /
• 1998

This study is carried out to investigate the characteristics of sound insulation performances for masonry walls. PC walls and ALC walls. For these purposes. 17 types of masonry walls were selected and tested in accordance with KS F 2808 at reverberation room The sound insulation performance of 8" cement block walls are graded with D-45 ∼ D-55 which are to be evaluated very favorable grade. 4" cement block walls are D-30 ∼ D-40. 1 B cement brick walls are D-40∼D-50 favorable grade. 0.5 B brick walls are D-30∼D-45. 150 mm PC wall is D-50. and ALC walls(150 mm, 200 mm) are D-30∼D-45.

• Journal of KSNVE
• /
• v.8 no.6
• /
• pp.1150-1157
• /
• 1998

In this Paper, we present an efficient method for finite element vibration analysis of constantly rotating structures with cyclic symmetry, which are deformed to some considerable extent by centrifugal force, Coriolis force and operating load, and vibrate due to several types of exciting forces. A structure with cyclic symmetry is composed of circumferentially repeated substructures with the same geometry. Being only one substructure modeled. the dynamic characteristics of the structure can be analyzed systematically. rapidly and exactly using discrete Fourier transform by means of a computer with small memory.

• Journal of KSNVE
• /
• v.11 no.1
• /
• pp.111-117
• /
• 2001

Present work deals with a study on the deployment or retraction of cantilever beam that includes the rigid-body motion of large displacement of beam through the translational and rotational motions in 2-dimensional plane. The equations of motion are derived with respect to non-Cartesian coordinate system. In the formulation of equations of motion, shear deformations and geometrically non-linear effect are included. An assumed mode method is applied and numerical convergence characteristics are studied also. Types of motion of the moving beam are assumed to be classified as‘slow’or‘fast’motion, and the dynamic characteristics are investigated.

• Proceedings of the KSRS Conference
• /
• 1999.11a
• /
• pp.421-424
• /
• 1999

The purpose of this study is to demonstrate a variety of methods for reducing the speckle noise content of SAR images, whilst at the same time retaining the fined details and average radiometric properties of the original data. In order to increase the accuracy of classification, Two categories of filters are used (speckleblind(simple), Speckle aware(intelligent)) and Segmentation of highly speckled radar imagery is achieved by the use of the Gaussian Markov Random Field model(GMRF). The problems in applying filtering techniques to different object types are discussed and the GMRF procedure and efficiency of the segmentation also discussed.

• Proceedings of the KIEE Conference
• /
• 2006.10d
• /
• pp.59-61
• /
• 2006

The single phase switched reluctance motor(SRM) is simpler in control circuit because the number of switching devices is fewer than the poly phase SRM. The energy density per unit volume is very big because all stator poles are excited simultaneously by a single switching power source. But it must be provided a starting device on account of not being generated the starting torque at specific rotor positions. And also it has some demerits that have a torque ripple, noise and vibration because of being excited by switching pulse power source. Therefore, to make up for these demerits, it is realized many studies for the structure design used by computer and the operating methods by power electronics technique. In this paper, we'll present the comparison of the single phase SRM with the various rotor pole face types, as like stepped rotor pole face type and general rotor pole face type. For the torque characteristics analysis.

• Journal of the Korea Safety Management & Science
• /
• v.2 no.4
• /
• pp.113-124
• /
• 2000

First, in order to improve selecting method of quality characteristic level desired by customers, S/N(Signal-to-Noise) ratio of Taguchi in larger-the-better characteristics was applied. Second, the Matrix classification standard of ACE(Attribute Categorization Evaluation) is presented using KANO model on difference analysis of importance and satisfaction through questionnaire from customers. This is for reflecting the diverse EC which customers want in EC quality sufficiently. Also, establishing sales point will be helpful in business strategy through presenting types that are able to decide planning quality. Third, the important measure of EC about correlation among quality characteristics and a new weight of EC are calculated depending on importance of EC and the weight of customer attribute and materials of relationship matrix through correlation matrix analysis.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.985-987
• /
• 1992

The three-phase full(6-pulse) bridge controlled rectifier is one of the most widely used types of solid-state converters in DC drive applications for higher performance. In most of the previous designs gate control circuits of the converter have been designed with analog method, whitch can be easily affected by noise. In this study microprocessor and pheripal LSIs are used for eliminating these problems and successful results have been obtained.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.52 no.1
• /
• pp.35-41
• /
• 2003

In this paper, a machine vision system for recognizing and classifying the patterns and marks engraved by die molding or laser marking on the glass panels of computer monitors is suggested and evaluated experimentally. The vision system is equipped with a neural network and an NGC pattern classifier including searching process based on normalized grayscale correlation and adaptive binarization. This system is found to be applicable even to the cases in which the segmentation of the pattern area from the background using ordinary blob coloring technique is quite difficult. The inspection process is accomplished by the use of the NGC hypothesis and ANN verification. The proposed pattern recognition system is composed of three parts: NGC matching process and the preprocessing unit for acquiring the best quality of binary image data, a neural network-based recognition algorithm, and the learning algorithm for the neural network. Another contribution of this paper is the method of generating the training patterns from only a few typical product samples in place of real images of all types of good products.

• Journal of KSNVE
• /
• v.5 no.4
• /
• pp.577-583
• /
• 1995

The sandwich type piezoelectric resonator is widely used for the acoustic sources of underwater acoustic transducers, whose important design parameters are shapes, materials, dimensions and supporting methods. Practical design method of resonators consists of manufacturing, experiments and modification so that it requires much time and expenses. In this study, an analytical design method of sandwich type piezoelectric resonators is presented based on the nonlinear optimization technique. The proposed method is applied to the design of an example resonator model in order to maximize the output powers. For the investigation of performance according to the division and their electrical connection, three types of resonators are manufactured. In addition, their dynamic characteristics such as electrical admittance and transmitting voltage response are measured and compared.