• Journal of Welding and Joining
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• v.24 no.5
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• pp.1-6
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• 2006

• Korean Journal of Mathematics
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• v.17 no.3
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• pp.245-248
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• 2009

We consider pm-ring with the property such that every prime ideal is contained in only one maximal ideal. Orsatti[4] characterized pm-rings by means of the retraction. Contessa[1] found algebraic condition, by using that direct product of pm-rings is a pm-ring. We show that C(X, H) and C(X, C) are pm-rings and we extend a quasi pm-domain.

• Mycobiology
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• v.36 no.2
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• pp.102-105
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• 2008

The acetylcholinesterase (AChE) inhibitor of Yarrowia lipolytica S-3 was maximally produced when it was incubated at $30^{\circ}C$ for 36 h in an optimal medium containing 1% yeast extract, 2% peptone and 2% glucose, with an initial pH 6.0. The final AChE inhibitory activity under these conditions was an $IC_{50}$ value of 64mg/ml. After partial purification of the AChE inhibitor by means of systematic solvent extraction, the final $IC_{50}$ value of the partially purified AChE inhibitor was 0.75 mg/ml. We prepared a test product by using the partially purified AChE inhibitor and then determined its stability for the development of a new antidementia commercial product. The test product was stable at room temperature for 15 weeks.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.200-205
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• 1993

The automatic forming sequence design system can determine desirable operation sequences even if they have little experience in the design of cold forging process. This system is proposed,which generates forming sequence plans for the multistage cold forging of zxisymmetrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning processes. Forming sequence for the part can be determined by means of primitive geometries such as cylinder,cone, convex, and concave. By utilizing this geometrical characteristics(diameter,height, and radius),the product geometry is expressed by a list of the pnmitive geometries. Accordingly, the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. The preliminary choice of some feasible forming sequences can verify by using the finite element simulation.

• Journal of the Korea Safety Management & Science
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• v.6 no.2
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• pp.187-197
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• 2004

The recycling cell formation problem means that disposal products are classified into recycling product families using group technology in their end-of-life phase. Disposal products have the uncertainties of product condition usage influences. Recycling cells are formed considering design, process and usage attributes. In this paper, a new approach for the design of cellular recycling system is proposed, which deals with the recycling cell formation and assignment of identical products concurrently. Fuzzy ART neural networks are applied to describe the condition of disposal product with the membership functions and to make recycling cell formation. The approach leads to cluster materials, components, and subassemblies for reuse or recycling and can evaluate the value at each cell of disposal products. Disposal refrigerators are shown as an example.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.36-43
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• 2003

In this paper, the warm forging process sequence has been determined to manufacture the warm forged product for the precision bevel gear used as the differential gear unit of a commercial automobile. The preform shape of bevel gear influences the dimensional accuracy and stiffness of final product. So, the design parameters related preform shape such as aspect ratio and chamfer length having an influence the formability of forged product are analyzed. Then the optimal conditions of design parameters have been selected by artificial neural network (ANN). Finally, to verify the optimal preform shape, the experiments of the warm forging of the bevel gear have been executed. The proposed method can give more systematic and economically feasible means for designing preform shape in metal forming process.

• Archives of design research
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• v.6 no.1
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• pp.1-10
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• 1993

This paper described design as a purposeful human activity for solving its problems. This means, problem solving is finding a way to get from some initial situation to a desired goal.In order to do this, like a voyage, there should be a compass, and a route map to guide the designer through the design process. Evaluation gives information about the way a design is proceeding and suggests the direction in which change should be made in order that the complex of design concepts should be fulfilled in a satisfactory manner.I think Pugh's total design model discussing in this paper takes a layered approach through a series of sequential actions, part of which is to find the product status. Each layer has the $$\mu$ti-dimensional elements, Product Design Specification (PDS) around the design core. I made a comparative study of several evaluation tools wi th Pugh's model and examined the criteria for evaluation and the rating / weighing methods.It needs, however, more study in order that PDSs may have its values and be fixed from the dynamic design concepts.

• 전기의세계
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• v.19 no.4
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• pp.1-11
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• 1970

It is well known that solid-state devices like inverter and converter made by transistor and other semi-conductors are widely used for the purpose of motor speed control in industrial fields. This paper is devoted primarily to a study of Trial Manufacturing of Solid-state Frequency Converter by means of single-phase bridge-type SCR inverter. The principle of the trial product belongs to AC-DC-AC conversion system. The voltage to be impressed to the motor in case of speed control by frequency conversion method is necessary to be proportional to frequency. It also requires the frequency and voltage are independent to hte load variation. In order to meet above requests required to motor speed control., the trial product introduced the open loop system in the frequency setting and closed loop system in the voltage setting. The trial product showed the favorable performance characteristics in speed control of singlephase fractional horsepower motor from 45HZ through 80HZ.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1266-1269
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• 2003

Many studies have indicated that most of a product's cost is fixed early in its lift cycle, before the original design cycle is complete. This implies that we should consider various aspects of product lift cycle at the design stage. This means the need of collaboration in design stage. Because the Internet provides instant access to a wealth of design information, the Internet is used by the collaborative design team members as a medium to share data, information and knowledge, and in some cases for product data management and project management by integrating the Web with appropriate technologies. This paper presents a real-time collaborative design system for powerful interaction performance, based on the Internet and Web technologies. Using The system use the client/server architecture and the purpose of the system is to provide a method that enables real-time view, review and modification of the 3D model through the Internet.

• The Journal of Society for e-Business Studies
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• v.6 no.2
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• pp.73-85
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• 2001

Usability is defined by the effectiveness, efficiency and satisfaction with which specified users can achieve specified goal in particular environment. Today, many factors such as software acquisition, business re-engineering and the trend of software market have software industry considers usability as an important quality of software products. Therefore, the specification and measurement method for establishing the acceptable usability level of software is required during software development acquisition and evaluation. To evaluate whether software products is usable or not, we need evaluation method for software usability. This paper is not only to provide a framework for specifying the usability attributes of a product and establishing a comprehensive set of usability criteria, but also assessing usability metrics of the software. The usability metrics and checklist is developed based on the properties of the user interface using ISO standard and general usability principles with product-oriented view which means the Product has attributes contributing to determine the usability. This paper also suggested the way to weight the relative importance of the individual usability item depending on the software categories.