• 한국기계가공학회지
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• 제19권9호
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• pp.47-52
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• 2020

With the 4th industrial revolution, condition monitoring using machine learning techniques has become popular among researchers. An overload due to complex operations causes several irregularities in MOSFETs. This study investigated the acquired voltage to analyze the overcurrent effects on MOSFETs using a failure mode effect analysis (FMEA). The results indicated that the voltage pattern changes greatly when the current is beyond the threshold value. Several features were extracted from the collected voltage signals that indicate the health state of a switched-mode power supply (SMPS). Then, the data were reduced to a smaller sample space by using a principal component analysis (PCA). A robust machine learning algorithm, the support vector machine (SVM), was used to classify different health states of an SMPS, and the classification results are presented for different parameters. An SVM approach assisted by a PCA algorithm provides a strong fault diagnosis framework for an SMPS.

• 대한안전경영과학회지
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• 제18권1호
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• pp.35-43
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• 2016

The past five years, industrial accidents due to food processing machinery have been occurred 725 cases, injury by the food cutter occurred 390 cases in its. On this study, to prevent food cutter injury, an attempt is made to present the improved documentation of fundamental safety of the food cutter workplace through the injury analysis of food cutter injury and surveys on band saw machine business field. Analyzing the result of 390 cases on food cutter injury, amputation, cut, puncture occupied 75.1 percent (293 cases), compressed occupied 23.3% (91 cases), also it showed constant component without reference to gender, age, scale of work place, service period. In the survey, lack of concentration for workers have been pointed out as the biggest factor in the cause of band saw machine injury. Meanwhile, such as the EU and Japan, whereas presents safety standards about band saw machines that are tailored to each country, on the other hand, South Korea doesn't provide the standards. To prevent the food cutter injury, safety standards need to be established in consideration of amputation, cut, puncture, compressed injury and financial support is required to procure protective equipment at each place of business.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.589-594
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• 1991

Group Technology (GT) is a technique for identifying and bringing together related or similar components in a production process in order to take advantage of their similarities by making use of, for example, the inherent economies of flow production methods. The process of identification, from large variety and total of components, of the part families requiring similar manufacturing operations and forming the associated groups of machines is referred as 'machine-component grouping'. First part of this paper is devoted to describing a hierarchical divisive algorithm based on graph theory to find the natural part families. The objective is to form components into part families such that the degree of inter-relations is high among components within the same part family and low between components of different part families. Second part of this paper focuses on establishing cell design procedures. The aim is to create cells in which the most expensive and important machines-called key machine - have a reasonably high utilization and the machines should be allocated to minimize the intercell movement of machine loads. To fulfil the above objectives, 0-1 integer programming model is developed and the solution procedures are found. Next an attempt is made to test the feasibility of the proposed method. Several different problems appearing in the literature are chosen and the results air briefly showed.

• 한국정밀공학회지
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• 제24권2호
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• pp.95-102
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• 2007

A feeding system is a key component in manufacturing packing boxes such as printing, slotting and gluing. The role of the feeding system is to feed corrugate cardboards which is usually tick and large. So, a special method is necessary to feed corrugate cardboards. This paper suggests a concept and an automatic feeding machine to feed corrugated cardboards using TRIZ, the theory of inventive problem solving. The automatic feeding machine consists of units to regulate the machine according to length and width of corrugated cardboards, a feeding part with a plurality of small rollers, and a sucking part which intensify frictional force between rollers and the lowest feeding cardboard. In particular, the feeding part is composed of an up-and-down motion plate with holes to suck the lowest corrugated cardboard as well as small rolling rollers after stopping in a moment. Thus this machine does not sensitive to size of corrugated cardboards and also can keep feeding accuracy during feeding fast.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권2호
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• pp.529-546
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• 2012

To address the need for autonomous control of remote and distributed mobile systems, Machine-to-Machine (M2M) communications are rapidly gaining attention from both academia and industry. M2M communications have recently been deployed in smart grid, home networking, health care, and vehicular networking environments. This paper focuses on M2M communications in the vehicular networking context and investigates areas where M2M principles can improve vehicular networking. Since connected vehicles are essentially a network of machines that are communicating, preferably autonomously, vehicular networks can benefit a lot from M2M communications support. The M2M paradigm enhances vehicular networking by supporting large-scale deployment of devices, cross-platform networking, autonomous monitoring and control, visualization of the system and measurements, and security. We also present some of the challenges that still need to be addressed to fully enable M2M support in the vehicular networking environment. Of these, component standardization and data security management are considered to be the most significant challenges.

• 전력전자학회논문지
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• 제18권5호
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• pp.437-442
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• 2013

For open-end permanent magnet synchronous machine(PMSM) with dual inverter system, where one inverter is connected to the source and the other is flying, the dc link voltage of the flying inverter can be boosted through the machine. For this reason, when compared with single inverter drive system, higher voltage can be applied to PMSM, and higher torque can be generated in the flux weakening region. In this case, however, active and reactive powers are separately supplied by each inverter to maintain the dc link voltage of flying inverter. Therefore, the required flux weakening control is different from the conventional method for a single inverter drive system. This paper proposes the novel flux weakening control method which maximizes the active voltage component in a dual inverter PMSM drive system. The proposed method was demonstrated and verified through experimental results.

• 반도체디스플레이기술학회지
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• 제18권2호
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• pp.38-43
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• 2019

In this study, a hydraulic press structure has been investigated in order to enhance the precision machining and the productivity, which are generally damaged by the structural deformation from the pressure and the vibrations originated from the centrifugal forces from the rotating parts of the machine. Computer simulation based on the finite element method has been utilized for the analysis of static and dynamic characteristics to investigate each component's critical points, and to further improve the static and dynamic stabilities of a hydraulic press structure. The result shows that the deformations and the vibrations of the machine could be reduced 35% without increasing the weight of the machine.

• Journal of Power Electronics
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• 제19권1호
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• pp.158-167
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• 2019

This research comparatively studies three kinds of flux regulation methods, namely, stored capacitor discharge pulse (SCDP), constant current source pulse (CCSP), and quantitative flux regulation pulse (QFRP), which are used for hybrid permanent magnet (PM) axial field flux-switching memory machines (HPM-AFFSMMs). Through an analysis of the operation principle and the series hybrid PM flux regulation mechanism of the objective machine, the circuit topologies and flux regulation process of these flux regulation methods are addressed in detail. On the basis of a simulation, the flux regulation characteristics of the researched machine during the magnetization and demagnetization processes are comparatively evaluated. Then, machine performance, including back EMF, direct and quadrature axis inductances, and magnetization and demagnetization characteristics, is quantitatively investigated. Results show that the QFRP enables the HPM-AFFSMM to achieve a less harmonic component of back EMF by approximately 7.28% and 7.97% at the magnetization and demagnetization states, respectively, and a more complete magnetization process than the SCDP and CCSP.

• 한국기계가공학회지
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• 제21권2호
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• pp.46-53
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• 2022

This paper presents the design and manufacture of a Solid State Relay (SSR) life prediction device that can predict the lifetime of an SSR, which is a key component of a glass forming machine. The lifetime of an SSR is over when the current supplied to the relay is overcurrent (20 A or higher), and the operating time is 100,000 h or longer. Therefore, the life prediction device for the SSR was designed using DSP to accurately read the current and temperature values from the current and temperature sensors, respectively. The characteristic test of the manufactured non-contact relay life prediction device confirmed that the current and temperature were safely measured. Thus, the SSR lifetime prediction device developed in this study can be used to predict the lifetime of an SSR attached to a glass forming machine.

• Advances in concrete construction
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• 제14권1호
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• pp.15-34
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• 2022

The use of waste rubber in concrete can reduce natural aggregate consumption and improve some technical properties of concrete. Although there are several equations for estimating the mechanical properties of concrete containing waste rubber, limited numbers of machine learning-based models have been proposed to predict the mechanical properties of rubbercrete. In this study, an extensive database of the mechanical properties of rubbercrete was gathered from a comprehensive survey of the literature. To model the mechanical properties of rubbercrete, M5P tree and linear gene expression programming (LGEP) methods as two machine learning techniques were employed to achieve reliable mathematical equations. Two procedures of input variable selection were considered in this study. The crucial component ratios of rubbercrete and concrete age were assumed as the input variables in the first procedure. In contrast, the volumes of the coarse and fine waste rubber and the compressive strength of concrete without waste rubber were considered the second procedure of the input variables. The results show that the models obtained by LGEP are more accurate than those achieved by the M5P model tree and existing traditional equations. Besides, the volumes of the coarse and fine waste rubber and the compressive strength of concrete without waste rubber are better predictors of the mechanical properties of rubbercrete compared to the first procedure of input variable selection.