• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.93-104
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• 2005

The present article discusses the number of empty convex 4-gons and empty convex 5-gons in a finite planar point set. New proofs are provided for the two related important results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.5
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• pp.629-635
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• 2009

Collapses of cutting area have frequently occurred due to heavy rainfall caused by the recent unusual weather patterns. Collapses of cutting area have the most crucial influence on the damaged property and casualties. Therefore, formulating and preparing an effective measures and control system is urgent. For this reason, in this study, we researched formation investigation method of location-based cutting area for an efficient management of cutting area. We conducted comparative and analytic research on the hand GPS method and DGPS method which is GPS augmentation system, using SBAS signals. The results of the research showed that there was difficult in discerning the accurate shape of cutting area when the existing method was used; however, the detecting the shape of four sides and accurate location was possible when DGPS was used. Consequently, it is possible to establish a preventive measures for cutting area, which considers the condition of the surrounding environment of cutting area because the polygon based management of incision cliff is attainable, apart from the existing control point based approach.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.1 no.1
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• pp.37-44
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• 1978

The purpose of this study is to search for an efficient application method in solving delay-phenomenon problems which influence upon total production cost through case study. The method of this study is an experimental study based on cutting time data in lead cutting operations from "Lead Cutting Machine (Stripper)" and its service rate data from a large electronic products company which utilizes conveyor line system for the products "Car Stereo" The procedure of this experimental study is as follows; 1) Using loading(Man-Hour) analysis technique j,1 order to analyse and evaluate Production capacity, efficiency, operation and idle rate assembly charge, waiting and service cost -when its are controlled by stripper operator(server) 2) Establishing adequate waiting time model of finite population caused by the interference of 4 stripper machine which is drawn from mathematical statistics testing, that is, goodness of fit test in the waiting and service rate and to search for optimal solution by utilizing the above mentioned model The experimental result was that amount to 8,546,618won Per year was brought down, that is, by optimum point, it shows a decrease as compared with Present point. The major limitation of this experimental study is that the Queue in the Finite Population, so to speak. it comes from the interference of 4 stripper machine dealt with this case were limited only on the Car Stereo conveyor line. Further study of application of this application method to the areas such as material handling, personnel management marketing and transportation management is strong1y recommended.trong1y recommended.

• Journal of Pharmaceutical Investigation
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• v.21 no.3
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• pp.155-160
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• 1991

Particulate is the foreign insoluble material in injectable solution inadvertently present in a given product. Considerable efforts have been made to avoid or minimize particulate contamination by pharmaceutical manufacturers during the production of parenteral products. Particulate contamination of the parenteral products can occur mainly during the opening (cutting) the container immediately before clinical use. In this study, particulate contamination generated during the opening process of ampoules (conventional type, 1-point and color-break ampoules) was compared with that of a prefilled injectable container (prefilled syringe). The particles were examined under a microscope after filtration of the total fluids in the containers. Particles having wide range of size distribution were found from all the ampoules tested. The contamination from the I-point ampoule and colorbreak ampoule was much less than from the conventional ampoule. Glass particles generated by cutting the glass-made ampoules seemed a principal source of the particulate contamination. The glass-partiaulte contamination could be improved substantially by replacing the ampoule containers with the prefilled syringe. Prefilled syringe, which can be used without any cutting process. did not generate particulates during the use. Therefore, it was concluded that prefilled syringe is most preferable container for the small volume parenteral (SVP) fluids in terms of particulate contamination.

• Journal of the Semiconductor & Display Technology
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• v.5 no.3 s.16
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• pp.5-10
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• 2006

This paper investigates cutting qualities after laser dicing and predicts the problems that can be generated by laser dicing. And through 3 point bending test, die strength is measured and the die strength after laser dicing is compared with the die strength after mechanical sawing. Laser dicing is chiefly considered as an alternative to overcome the defects of mechanical sawing such as chipping on the surface and crack on the back side. Laser micromachining is based on the thermal ablation and evaporation mechanism. As a result of laser dicing experiments, debris on the surface of wafer is observed. To eliminate the debris and protect the surface, an experiment is done using a water soluble coating material and ultrasonic. The consequence is that most of debris is removed. But there are some residues around the cutting line. Unlike mechanical sawing, chipping on the surface and crack on the back side is not observed. The cross section of cutting line by laser dicing is rough as compared with that by mechanical sawing. But micro crack can not be seen. Micro crack reduces die strength. To measure this, 3 point bending test is done. The die strength after laser dicing decreases to a half of the die strength after mechanical sawing. This means that die cracking during package assembly can occur.

• 한국기계연구소 소보
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• s.19
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• pp.69-79
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• 1989

Cutting tool life monitoring is a critical element needed for designing unmanned machining systems. This paper describes a tool wear measurement system using computer vision which repeatedly measures flank and crater wear of a single point cutting tool. This direct tool wear measurement method is based on an interactive procedure utilizing a image processor and multi-vision sensors. A measurement software calcultes 7 parameters to characterize flank and crater wear. Performance test revealed that the computer vision technique provides precise, absolute tool-wear quantification and reduces human maesurement errors.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.8
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• pp.720-725
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• 2011

Most ultrasonic vibration cutting tools are operated at the resonance condition of the longitudinal vibration of the structure consisting of booster, horn and bite. In this study, a transverse vibration tool with beam shape is designed to utilize the vibration characteristics of the beam. Design point of the transverse vibration tool is to match the resonance frequency of the bite to the frequency of the signal to excite the piezoelectric element in the booster. The design process to match the natural frequency of the longitudinal vibration mode of the horn and that of the transverse vibration mode of the bite is presented. Dimensions of the horn and bite are searched by trend analysis through which the standard shapes of the horn and bite are determined. After the dimensions of each component of the cutting tool consisting of booster, horn and bite are determined, the assembled structure was experimentally tested to verify that true resonant condition is achieved and proper vibrational displacement are obtained to ensure that enough cutting force is generated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.38-44
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• 2008

Titanium and its alloys, due to their superior properties of high specific strength and excellent corrosion resistance, are increasingly used in living applications in the 21century. The applications in aerospace and medical industries demand machining process more frequently to obtain a desired product. But unfortunately, this material is one of the most difficult-to-cut. In the turning process of titanium alloys, the key point for successful work is to select proper tool materials and cutting conditions. This study suggests a guidance for selecting the tool materials and the cutting speeds to improve tool life and surface integrity in Ti-6Al-4V titanium turning process. The experiments investigate the change of surface roughnesses, cutting forces and flank wear with various cutting parameters of tool materials, depth of cuts and feeds. As the results, K10 type of insert tip was assured as the best for turning of Ti-6Al-4V titanium alloy.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.8
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• pp.73-81
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• 1997

The hard turning process defined as a single point turning of materials harder than $H_{R}$C 58 differs from conventional turning because of hardness of the work materials and cutting toos needed in the process. In hard turning, tool life is very short, of the order of a few minutes, during which the cutting tool is subjected to the extremes of stress and temperature. In this regard, it is well known that CBN tool is proper for this process in spite of expensive cost. In this research, we studied the feasibility of the use of the low cost cutting tool such as a aTiN coated tool. To this end, a new cooling system was designed with an air-oil method for reducing tool temperature, which is based on the principle of air vortex flow. That is, the outlet temperature of the air becomes aver 20 .deg. C lower than atmosphere temperature by entering pressurized air of 5kgf/c $m^{2}$ into the inlet. This cooled air ejected to the top of the cutting tool lowered tool temperature, which reduced the wear of a TiN coated tool by the 30% of CBN tool life with respect to the same cutting length.h.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.30-39
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• 2010

This paper considers a problem of optimizing torch paths to cut stock plates nested with open contours. For each contour, one of the two ending points is to be selected as a starting point of cutting with the other being the exit point. A torch path is composed of a single depot and a series of starting and ending points of contours to be cut. The torch path optimization problem is shown to be formulated as an extended version of the standard travelling salesman problem. To solve the problem, a hybrid genetic algorithm with the local search of torch paths is proposed. The genetic algorithm is tested for hypothetical problems whose optimal solutions are known in advance due to the special structure of them. The computational results show that the algorithm generates very near optimal solutions for most cases of the test problems, which verifies the validity of the algorithms.