• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.493-502
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• 1999

Majority of livestocks are kept in the tropics. Demand for animal products (meat and milk) is continuously increasing and is related to human population growth. Consequently, potential feeds should be continuously identified particularly on their nutritive values. Crop residues and agricultural by-products are the main feed sources for feeding livestock in the tropics. Their nutritive values ranging from low to medium quality level although Some agricultural by-products such as cotton seed meal and coconut meal are rich in nitrogaen contents. From literatures, nutritive values in these ingredients are mainly based on their chemical composition and to some extent based on limited number of in vivo studies. However, optimum of inclusion in the diet is suggested. Development of tree legumes should be thoroughly considered since they grow well in most tropical regions. In order to improve nutritive value of tropical feeds, biological treatments should be considered. Effect of secondary compounds decreasing efficiency of nutrient utilization in the rumen, to some extent could be reduced by introducing probiotics.

• Feed Journal
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• v.3 no.7 s.23
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• pp.115-121
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• 2005

최근 곰팡이에 오염된 사료를 먹은 애완동물의 대규모 폐사 및 급만성의 신장질환에 대한 문제가 우리나라를 비롯한 동남아시아에서 큰 이슈가 되었다. 이 사건은 우리나라에서의 애완동물에 대한 사회적인 인식의 변화와 또한 이미 TV등의 언론 매체를 통해서 널리 퍼져 있는 반려동물로서 그들의 복지와 권리에 대한 인식을 재고하는 계기가 되었다고 볼 수 있다. 이러한 사건을 보면서 정작 우리의 식탁에 오르고 있는 가축의 먹이, 즉 사료에 대해서는 사회적인 관심이 부족한 것이 아닌가 하는 생각이 든다. 최근 웰빙(well-being) 바람과 함께 생활 전반에 친환경 및 유기농에 대한 소비자들의 관심 증가와 요구가 늘어나고 있는 실정이다. 하지만 우리의 주요 육류 공급원인 소나 돼지 등의 가축들이 먹고 자라는 사료에 대한 관심은 섭섭한 마음이 들 정도로 부족하다. 이러한 시점에서 효율적인 사료관리를 통한 질병 제어 및 국민의 양질의 육류섭취를 위한 축산물 생산에 대해 얘기보고자 한다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.39-45
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• 2012

Currently, the aircraft industry, aircraft parts as well as airframe have been developed in producing, the aircraft parts and fuselages have been produced the product by cutting rather than forging and casting because of the residual stress and stress concentration. In this study, the aircraft is being used in many parts of aluminium alloy 2024 in wire-cut E.D.M. The selected experimental parameters are peak current, no-load voltage, off time and feed rate. It is found that cutting mountain part on surface roughness of the curve 0.3mm than 0.25mm diameter wire electrode is stable in many uniform distribution.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.86-92
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• 2002

This paper presents a new model of NC verification in NC milling using z-map. The model can describe the motion of machine tool like a real machine effectively. The model uses x, y, and z directional feed rate as well as cutting data for modeling Z-map of workpiece. The model verifies the over-cut, the under-cut and the surface topography using NC codes and cutting conditions. To investigate the performance of the model, simulation study was carried out. As the results, the model gave the geometry accuracy of workpiece, the surface topography, and the chip loads.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.263-268
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• 1998

Development of high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of the tool change time as well as rapid travel time can enhance the productivity. However, the high speed feed drive system generates more heat in nature, which leads thermal expansion that has adverse effects on the accuracy of machined parts. The detail of the model proposed is described in the paper together with the experimental methodologies using a proposed compact measurement system to examine the validity of the proposed approach. The results showed the machining accuracy could be maintained to better than $\pm$5${\mu}{\textrm}{m}$ while using this T-18 sensor

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.163-170
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• 2002

This paper presents some measures far the optimization of the thermal behavior of linear motors, which are used as a high speed feed mechanism in machine tools. Thermo-Sandwich-Construction using two cooling circuits and an insulation layer shows an effective cooling system for linear motors. Conducting sheet can be also used to reduce heat flow from linear motor to machine table. Cooling pipe is a simple and effective cooling system for the secondary part of synchronous linear motor. Through the combination of the Thermo-Sandwich-Construction, conducting sheet and cooling pipe the thermally optimized linear motor shows a well improved thermal behavior in comparison with the prototype motor.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.257-262
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• 1999

On End Milling Process predict the cutting force is important. Dynamics the shear stress is the main parameter influencing the energy requirement in machining. It is well known that a nonzero force is obtained when cutting forces measured at different feed rates but otherwise constant cutting conditions are extrapolated to zero feed rate. In this paper, the cutting force measured in end-milling is compared with the simulated force models. The result show that stress measured in cutting is consistent with that stresses predicted.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.98-102
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• 1994

There are many difficulties in automatic polishing for die & mold surfaces. Even though the process has been studied in the past 15 years, it has not been achieved yet, but by the process of actual hand work of well-skilled workers. A new magentic assisted polishing process, which is one of the potential method for automation of surface finishing has been studied in the past 10 years by colleagues. The process has many merits, but on the other hand also has demerits, one being low efficiency of gridability by comparision with grinding wheel polish. Therefore, some attempts were tried to improve the grindability by adopting electropolishing, ultra-high speed milling, 5-axis controlled machine etc... most recently by collegues. This study also aims to improve the efficiency of polishing by introducing the easily-polished shape surface milling method equalizing the tool feed per tooth to the pick feed. This milling method was experimentally confirmed to have sufficient grindability to polish milled surface (with 10 .mu. mRmax surface roughness) into mirror surface (with 0.4 .mu. mRmax surface roughness).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1025-1028
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• 2002

In this paper, a micro-turning lathe is introduced for micro machining of aluminum rod. To give feed motion, stepwise motion[2] actuators are used instead of the conventional inchworm mechanism. These are consisted of two Piezoelectric ceramics; one is for feeding the slider, and the other is for clamping the slider in the guide way of the body. The guide is V-form. The linearity and positional accuracy of the actuators is good enough far high precision motion. Since the system is more compact than the conventional system using three Piezoelectric ceramics, it is applicable for the micro-machine or MEMS unit. To fabricate the lathe, a small spindle unit with ball bearings of diameter of 10 millimeter is built-up on the top the slider. The motion is feed backed with miniaturized linear encoder attached each axis slider. The diamond tool bite is used for cutting tool. The machining is tried to make small diameter rod. The possible diameter that can be machined in this machine is presented as well as chip formation, surface roughness, and machinability.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.180-192
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• 1998

This paper introduces a new self-organizing fuzzy logic controller (SOFLC) for precision contour machining in the presence of large disturbances which adjusts both input and output membership functions simultaneously. The parameters of the proposed controller are self-tuned in real-time according to a continuous measurement of the performance of the controller itself and estimated disturbance values. The proposed controller as well as a conventional fuzzy logic controller and a PID controller were simulated and implemented on a 3-axis milling machine in contour milling. Both the simulations and experiments show that the self-organizing fuzzy logic controller has superior performance in terms of contour tracking accuracy compared with the other two controllers.