• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.11
• /
• pp.167-173
• /
• 2002

The look up table method conventionally applied to control the inner temperature and humidity of a laver drying machine has repeatedly occurred not only laver's damage but also inferior goods since the reaching time at the optimum state takes a long time. In this paper, a fuzzy control theory instead of the look up table was proposed to reduce the reaching time at the optimum state. The proposed method used six input variables and four output variables for the fuzzy control, and a triangle rule for a fuzzifier, The Mandani's min-max method was applied to a fuzzy inference. Also, the mean method of maximum was applied to a defuzzifier. The method applied to the fuzzy controller contributed to reduce the reaching time at the optimum state, and to minimize not only laver's damage but also inferior goods.

• Journal of Institute of Control, Robotics and Systems
• /
• v.6 no.6
• /
• pp.486-491
• /
• 2000

The dicing process cuts a semiconductor wafer to lengthwise and crosswise direction by using a rotating circular diamond blade. But inferior goods are made under the influence of several parameters in dicing such as blade, wafer, cutting water and cutting conditions. This paper describes a monitoring algorithm using neural network in order to find out an instant of vibration signal change when bad dicing appears. The algorithm is composed of two steps: feature extraction and decision. In the feature extraction, five features processed from vibration signal which is acquired by accelerometer attached on blade head are proposed. In the decision, back-propagation neural network is adopted to classify the dicing process into normal and abnormal dicing, and normal and damaged blade. Experiments have been performed for GaAs semiconductor wafer in the case of normal/abnormal dicing and normal/damaged blade. Based upon observation of the experimental results, the proposed scheme shown has a good accuracy of classification performance by which the inferior goods decreased from 35.2% to 6.5%.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.5
• /
• pp.70-75
• /
• 2000

After the patterning and probe process of wafer have been achieved, the dicing process is necessary to separate chips from a wafer. The dicing process cuts a wafer to lengthwise and crosswise direction to make many chips by using narrow circular rotating diamond blade. But inferior goods are made under the influence of complex dicing environment such as blade, wafer, cutting water and cutting conditions. This paper describes a monitoring algorithm using feature extraction in order to find out an instant of vibration signal change when bad dicing appears. The algorithm is composed of two steps: feature extraction and decision. In the feature extraction, two features processed from vibration signal which is acquired by accelerometer attached on blade head are proposed. In the decision. a threshold method is adopted to classify the dicing process into normal and abnormal dicing. Experiment have been performed for GaAs semiconductor wafer. Based upon observation of the experimental results, the proposed scheme shown a good accuracy of classification performance by which the inferior goods decreased from 35.2% to 12.8%.

• Proceedings of the Korean DIstribution Association Conference
• /
• 2000.10a
• /
• pp.187-205
• /
• 2000

6 Sigma movement is the quality innovation activity which Motorola, a nineteen eighties' top-ranking American company of electronics and communication, has started to survive the Japanese companies' frightening gami-gaze. In early days, it's just applicated for reducing customers' complain by eliminations inferior goods centering round producing activity and filling up the competitive market's demand for price and delivery deadline. Nowaday, 6 Sigma application has created a boom extending to a company's most activity fields without any exact scrutiny of 6 Sigma. Although 6 Sigma movement starts from the question of what customers want not by cutting off the inferiority rate but by cutting out causes of producing inferior goods, the service industry has a special character that makes it difficult to compute the level of Sigma. Thus this research examines suitability for introduction of 6 Sigma to the Service Industry.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
• /
• v.6
• /
• pp.186-197
• /
• 1993

• Journal of Korea Trade
• /
• v.23 no.3
• /
• pp.20-37
• /
• 2019

Purpose - The purpose of this paper is to analyze the trade structure and competitiveness of China's information technology (IT) industry in comparison to that of Korea and the United States, particularly in terms of quality. Design/methodology/approach - Indices such as trade specialization index (TSI), Revealed Comparative Advantage (RCA), and Market Comparative Advantage (MCA) are used. Further, an Intra-industry Trade (IIT) index is used to analyze qualitative changes in horizontal intra-industry trade and intra-industry trade of high- and low-quality goods. Findings - China's IT industry has a comparative competitive advantage over that of Korea and the United States, and mainly exports goods of inferior quality and imports goods of superior quality. Further, China's horizontal intra-industry trade has been decreasing, while its vertical intra-industry trade has been increasing and vertical trade of inferior quality goods outweighs that of superior quality goods. This shows that China is rapidly catching up with Korea and the United States, even though its qualitative competitiveness has not significantly improved. Research limitations/implication - This study has academic and political implications, as it analyzes changes in China's IT trade competitiveness. However, it is somewhat limited as factors determining qualitative aspects has not been considered. Originality/value - Most studies aggregate analyses of export competitiveness using methodologies such as TSI, RCA, and market share. However, the focus of these methods is price competitiveness. Hence, an examination of the objective and qualitative trade competitiveness of China's IT industry is necessary. this study the trade structure and quantitative competitiveness of the industry by analyzing intra-industry trade focusing on the quality of competitiveness. Therefore, the changes in China's IT industry in the USA and Korea and in foreign trade competitiveness and quality competitiveness are clarified. The results show that the academic and policy implications of these changes in the IT industry will be a useful resource. This is the first study in Korea to attempt such an analysis. This is the first study in Korea to attempt such an analysis.

• Journal of Korean Institute of Fire Investigation
• /
• v.11 no.1
• /
• pp.1-8
• /
• 2008

The purpose of this paper is to report gas fire accident based on classification of the major gas fire causes (including handling mistakes, inferior goods, etc.), fire classifications (fire, explosion, leakages, etc.), damage levels(1st, 2nd, 3rd, 4th grade levels), casualties (death, serious wound, slight injury) since gas fire has been generated according to growth of gaseous fuel consumption on home and enterprises with various accident causes. Among gaseous fuels, LPG facility can be c1assified as gas container, pressure regulator, gas hose, interim valve, combustion port. Any fire or any explosion can be caused from handling mistakes, inferior goods on each parts as stated above. Exact gas fire causes shall be identified based on previous case studies on similar fires with consideration of lesson learns.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.649-652
• /
• 2005

The camera cellular phone has a large portion of cellular phone market in recent year. The variety of a customer demand makes a fast model change and the spatial resolution is changed from VGA to multi-mega pixel. The 1.3 mega pixel (MP) camera cellular phone was first released into the Korean market in October 2003. The major cellular phone companies released a 2MP camera cellular phone that supports zoom function and a 2MP camera cellular phone is settled down with the Korea cellular phone market. It makes a keen competition in price and demands automation for phone camera module. There is an increasing requirement for the automatic assembly to correspond to a fast model change. The hard automation techniques that rely on dedicated manufacturing system are too inflexible to meet this requirement. Therefore in this study, this system is designed with the flexibility concept in order to cope with phone camera module change. The system has a same platform that has X-Y-Z motion or X-Z motion with ${\mu}m$order accuracy. It has a special gripper according to the type of a component to be put together. If the camera model changes, the gripper may be updated to fit for the camera module. The controller of this system acquires the data sets that have the information about the assembly part by the tray. This information is obtained ahead of an inspection step. The controller excludes an inferior part to be assembled by using this information to diminish the inferior goods. The assembly jig used in this system has a function of self adjustment that reduces the tact time and also diminish the inferior goods. Finally, the intelligent assembly system for phone camera module will be designed to get a flexibility to meet model change and a high productivity with a high reliability.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.3 no.3
• /
• pp.32-38
• /
• 2004

Recently, the system of high speed milling(HSM) is widely used for reducing the operation time and maximizing efficiency of work. The most research of high speed milling system is still leaves much to be desired. Specially the research of mass pocket high speed processing with high precision is the first and probably the last. So this paper showed mass pocket processing of high precision with a duralumin and then confirmed a cause of inferior goods through the CAD/CAM pattern simulation and experimentation. And this paper showed high speed processing system reduce the rate of inferior from this optimal pattern.

• Proceedings of the KWS Conference
• /
• 2005.06a
• /
• pp.331-333
• /
• 2005

It comes up conversation in automobile industry that some technologies related to production and quality for goods have to be developed to make rationalization of the unit cost of production because material of car muffler is replaced by expensive stainless steel having corrosion-resistance and oxidation-resistance. Quality evaluation and control is direct method for the company producing welded goods in large quantities to increase productivity and to improve quality. It seems that prevention of inferior quality and increasement of productivity will be hard if production design does not have quality evaluation method related to weld assembly, They have been producing welded goods using MIG weld but still do not have not only quality evaluation method but also evaluation criterion for welded joint. In this study, the way for development of quality evaluation method is showed by analysis and calculation of waveform to improve technology related to welding process