• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.231-234
• /
• 2002

Ultrasonic machining technology has been developed over recent years for the manufacture of cost-effective and quality-assured precision parts for several industrial application such as optics, semiconductors, aerospace, and automobile. Ultrasonic machining process is an efficient and economical means of precision machining of ceramic materials. The process is non-thermal, non-chemical and non-electric and hardly creates changes to the mechanical properties of the brittle materials machined. This paper describes the characteristics of the micro-hole of $\textrm{Al}_2\textrm{O}_3$ by ultrasonic machining with tungsten carbide tool. The effects of various parameters of ultrasonic machining, including abrasives, machining force and pressure, on the material removal rate, hole quality, and tool wear presented and discussed. The ultrasonic Machining of micro-holes in ceramics has been under taken and the machining mechanism in the ultrasonic machining of ceramics based on the fracture-mechanics concept has been analyzed.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.8
• /
• pp.65-75
• /
• 2016

In this paper, we present a novel approach to help MSR researchers obtain necessary data with a tool, termed General Purpose Extractor for Source code (GPES). GPES has a single function extracts high-quality data, e.g., the version history, abstract syntax tree (AST), changed code diff, and software quality metrics. Moreover, features such as an AST of other languages or new software metrics can be extended easily given that GPES has a flexible data model and a component-based design. We conducted several case studies to evaluate the usefulness and effectiveness of our tool. Case studies show that researchers can reduce the overall cost of data analysis by transforming the data into the required formats.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09b
• /
• pp.883-884
• /
• 2006

A new extra-fine grade Ni powder (XF Ni) has demonstrated increased sintering activity in Co-Fe-Ni binders for diamond tool applications. XF Ni has the advantage of significantly lower cost than XF Co. Up to 30% of XF Co was substituted with XF Ni while maintaining comparable apparent hardness and transverse rupture strength to pure Co binders. Ni substantially increased the diffusion of Fe. Diamond tool producers can take advantage of the improved sintering properties of XF Ni powder to substantially lower material costs.

• Korean Journal of Computational Design and Engineering
• /
• v.6 no.4
• /
• pp.222-228
• /
• 2001

In the milling operation, the burr can be generated on the intersection of cutting tool and workpiece. Due to burr formation, we expect lower efficiency in the operation and the cost increase. In order to understand the burr formation mechanism in the milling operation on the arbitrary feature, we developed an algorithm to analyse and predict the exit burr formation mechanism. Firstly, the recognition of arbitrary shaped workpiece was done through the CAD data. This data includes point information on the vertices of the workpiece. Secondly, tile CAM data regarding tool geometry, tool path, cutting speed, and material data are retrieved to simulate the actual cutting process. Thirdly, we predict the exit burr formation on the edge of workpiece based on the geometric analysis. Lastly, an algorithm implemented in the Windows environment to visualize the burr formation simulation. With this information, we can predict which portion of workpiece would have the exit burr in advance so that we call manage to find a way to minimize the edit burr formation in the actual cutting.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.21 no.45
• /
• pp.265-277
• /
• 1998

The control chart has been used widely and importantly as a tool for statistical process control(SPC). Most companies are concerned with improving the quality and the productivity as well as reducing the cost, especially in today's highly competitive environment. Though SPC is known as a technique for consistent quality, it is not used properly due to lack of knowledge about it. It is required to develop a support system for control chart selection and interpretation that can be utilized by non-specialist without hard training or experiences. The support system was developed by applying the expert system tool to popular control charts. Though some researches on this area has been performed, the implemented results expose many problems in field applications due to the unsatisfactory explanation of the selected control chart and limited knowledge base for resolving the problems. This thesis presented an expert system for control chart as solution for these problems. The expert system for the control chart selection and interpretation is developed by using Turbo C and EXSYS which is an expert system development tool.

• Proceedings of the KIEE Conference
• /
• 2005.10c
• /
• pp.337-339
• /
• 2005

A photovoltaic panel is a device that, through the photovoltaic effect, converts luminous energy into electric energy. Photovoltaic generation system uses infinity of sofa energy, cost of fuel is needless and there is no air pollution or waste occurrence. This paper summarizes the results of these efforts by offering a photovoltaic system structure in 50kW large scale applications installed in Chosun University dormitory roof and simulation tool. This describes configuration of utility interactive photovoltaic system which generated power supply for dormitory. In this Paper represent 50kW utility PV system examination result.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.564-567
• /
• 2005

For the application of monitoring system of the machine tool to industry, the requirements such as high reliability and low cost need to be satisfied. In this study, a reliable but inexpensive monitoring method for machine tool is introduced. To improve the monitoring reliability, several kinds of information related to machining and operation are selected; real-time video clip from USB camera, operation data and signal from CNC and feed motor torque. Especially, to improve the quality of real-time video clip, a camera housing is developed, it can significantly reduce the vibration effect and prevent from coolant and chip. The collected information are transferred to the monitoring terminals in remote sites using OPC and TCP/IP protocol over Ethernet, which give us convenience of development and interoperability.

• International conference on construction engineering and project management
• /
• 2005.10a
• /
• pp.820-823
• /
• 2005

RFID technology offers the possibility that tools and valuable supplies tagged with RFID devices could be tacked down automatically. Such automated tool tracking has the potential to reduce theft, identify underutilized tools to be relocated, insure that crafts have access to the appropriate tools as needed, and reduce overhead labor cost of managing tools. Although other industries have been busy to enhance their supply chain management using RFID technology, construction professionals may be wondering whether it works reliably in construction jobsites as well. This paper presents a field test conducted to determine the reliability of RFID technology in identifying tools in the field storage box. The test indicated that RFID technology is reliable in inventorying tools in field storage.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.1
• /
• pp.22-28
• /
• 1995

Micro Drills have found ever wider application. However micro drilling is a machining to integrate the difficult machinablities such as tool stiffness, position control and revolution accuracy, and is known to cost and time consuming. So, this study aimed to practice ultraminiature drilling(0.05 .phi. ) wiht simple component, if possible. System is developed as the three modules : feed drives, spindle and monitoring part. The dynamics of measured current signals from the spindle of Micro Hole Drilling machine are investigated to establish the criteria of stepfeed mechanism. Cutting experiments identify the relationship of spindle rpm, feed rate and tool life. The smaller drill diameter is, the more suitable cutting condition have to be selected because of chip packing.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.2
• /
• pp.30-38
• /
• 2020

Inadequate cost management has widely been recognized as one of the most problematic areas in the Korean construction industry as many believes that public cost references are not reasonably reflecting the market conditions. 'Total Project Cost Management Guideline' developed by Ministry of Economy and Finance(MOEF) to govern public budget control has been identified as one of the main reasons for this problem. This study attempts to thoroughly review 'Total Project Cost Management Guideline' itself and quantitatively analyze the impact of it on project cost during procurement process. Different procurement methods are considered including turnkey & alternative, private contract, qualification examination, and lowest price bidding system in this quantitative impact analysis of 'Total Project Cost Management Guideline'. Analysis results shows that this governmental process works mainly as a constant cost-cutting tool throughout the procurement process.