• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.491-494
• /
• 2002

The real-time industrial network often referred to as fieldbus, is an important element for building automated manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices such as sensors, actuators, and controllers. numerous standard organizations and vendors have developed various fieldbus protocols such as Profibus, WorldFIP and Foundation Fieldbus. However, the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multi-vendor products. In order to solve these problems, the computer network technology, especially Ethernet (IEEE 802.3), is being adopted lo the industrial environment. The crucial technical obstacle for Ethernet is that its non-deterministic behavior makes it inadequate for industrial applications where real-time data such as control command and alarm signal hale to be delivered within a certain time limit. Recently, the development of switched Ethernet shows a very promising prospect for industrial application due to the elimination of uncertainties in the network operation resulting in much improved performance. This paper focuses on the application of the switched Ethernet for industrial comm unications.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.494-497
• /
• 2002

The purpose of this study is to establish a prototype system for effective construction safety management. The research method involves comparison and adaptation into construction of quality and environment management systems in foreign and domestic manufacturing fields. The results of this study we as follows: The suggested model for construction safety management can be used effectively for the parties such as employer, employees, stakeholders, and the public especially through the application of performance measuring and reporting system.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.1 s.17
• /
• pp.80-87
• /
• 2004

This paper presents an analysis of construction project management from supply chain management perspective to gain insight from all constituents and to identify areas of improvement. In order to suggest opportunities for improvement, interviews with the members of a typical urban office building project in US were held. Based on that, a qualitative analysis of construction projects is presented. Focusing on electrical and mechanical sub-systems, this study illustrates the roles of subcontractors, suppliers, distributors, and manufacturing representatives as well as the complexity that a general contractor fares in managing its supply chain. The author$^{\circ}\phi$s recommendations are focused on process restructuring and automation, which include some quantifiable performance measures, incentives, and their alignment with each other

• Journal of Electrical Engineering and Technology
• /
• v.2 no.3
• /
• pp.320-328
• /
• 2007

The sheath in underground power cables serves as a layer to prevent moisture ingress into the insulation layer and provide a path for earth return current. Nowadays, owing to the maturity of manufacturing technologies, there are normally no problems for the quality of the sheath itself. However, after the cable is laid in the cable tunnel and is operating as part of the transmission network, due to network construction and some unexpected factors, some problems may be caused to the sheath. One of them is the high sheath circulating current. In a power cable system, the uniform configuration of the cables between sections is sometimes difficult to achieve because of the geometrical limitation. This will cause the increase of sheath circulating current, which results in the increase of sheath loss and the decrease of permissible current. This paper will study the various characteristics and effects of sheath circulating current, and then will prove why the sheath current rises on the underground power cable system. A newly designed device known as the Power Cable Current Analyser, as well as ATP simulation and calculation equation are used for this analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.185-190
• /
• 2007

In recent days, vibration isolation system is mostly required in precise measurement and manufacturing system to reduce vibration due to external disturbances and internal actuators. Among all the vibration isolation systems, air spring is widely used because of its low resonant frequency and high damping ratio. In this study, we first analyze the passive air-spring system using leveling valve, and then design the active vibration isolation system. Because the non-linearity of pneumatic characteristics, we try to design the fuzzy controller which is better than PID controller at complex and non-linear system, and then compare them both in experiment and simulation.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.31 no.3
• /
• pp.101-109
• /
• 2008

This paper considers an integrated decision for scheduling and outsourcing(or, subcontracting) of a finite number of jobs(or, orders) in a time-sensitive make-to-order manufacturing environment. The jobs can be either processed in a parallel in-house facilities or outsourced to subcontractors. We should determine which jobs should be processed in-house and which jobs should be outsourced. And, we should determine the schedule for the jobs to be processed in-house. If a job is determined to be processed in-house, then the scheduling cost(the completion time of the Job) is imposed. Otherwise(if the job should be outsourced), then an additional outsourcing cost is imposed. The objective is to minimize the linear combination of scheduling and outsourcing costs under a budget constraint for the total available outsourcing cost. In the problem analysis, we first characterize some solution properties and then derive dynamic programming and branch-and- bound algorithms. An efficient heuristic is also developed. The performances of the proposed algorithms are evaluated through various numerical experiments.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.32 no.3
• /
• pp.20-28
• /
• 2009

Member's perception toward organizational climate is an concept but generally it has been used in the meaning of Organizational climate by members, in an attempt to give an idea of what kind of meaning an organization can have from a psychological point of view to its members. This thesis insists Individual attitudes in the organization be changed characteristics of organization and individual who percepts the organization, one the basis of Organization climate effects individual attitudes directly and indirectly, and objective of the study is to verify the dependence of cause and effect between organization climate and job satisfaction and performance with manufacturing firms within Gumi National Industrial Complex. As a result, to promote the effectiveness and efficiency of the enterprise, firstly, we have to set an appropriate objectives within the organization, Secondly, the manager should recognize the controversial issue be solved in public. Lastly, the members should be inspired loyalty into their organization.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2160-2163
• /
• 2005

Solid freeform fabrication (SFF) technology plays a major role in industry and represents a reasonable percentage of industrial rapid prototyping/tooling/manufacturing (RP/RT/RM) development applications. However, SFF technology still has long way to progress to achieve satisfactory process speed, surface finish and overall quality improvement of its application. Today, three dimensional printing (3DP) technique that is one of SFF technology is receiving many interests, and is applied by various fields. It can fabricate three dimensional objects of solid freeform with high speed and low cost using ink jet printing technology. However, need long curing time after manufacture completion. And it must do post-processing process necessarily to heighten strength of objects because strength of fabricated objects is very weak. Therefore, in this study, we proposed an improved 3DP process that can solve problems of conventional 3DP process. The general 3DP process is method to spout binder simply through printer head on powder, but proposed process is method to cure jetted UV resin by UV lamp after jet UV resin using printhead on powder. The hardening of resin is achieved strongly at early time by UV lamp in proposed method. So, the proposed process can fabricate three dimensional objects with high speed without any post-processing.

• Korean Journal of Computational Design and Engineering
• /
• v.16 no.5
• /
• pp.351-360
• /
• 2011

Product systems are quickly and frequently changed because Product Life Cycle is continuously reduced and adopting new product is steadily fast. Thus, various studies are progressed using simulation which is one of digital manufacturing. The research that is concerning simulation of control verification for shorten the commissioning which has a lot of trial and error is in progress. Also, simulation of control verification has strength that it can catch the errors in advance. However, a control program in simulation needs virtual factory for representation of control information. For this reason, excessive time and energy is put into controlling the virtual factory. So, in this paper, we construct library which is using exist data, in order to overcome limitation of these problems. Furthermore, we suggest methodology which can model and verify the process more speedy using library. Especially, we give body to the BB/BR Line process which has many altering equipment and need high technology effectively using physical and logical modeling. We can set up a control simulation environment very rapidly, as well as cut process time down using our suggestion.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.377-380
• /
• 2001

A recent trend in flexible manufacturing systems(FMS) is to compose of the identical versatile-machines and to use dynamic tool allocation strategy, sharing tools between machines with fast tool delivery system. Unlike a conventional FMS where parts are fed to the machines with the required tools, tools are acquired from other machines using a tool delivery system and parts can be finished on the same machine in these FMS. Therefore it is more important problem to plan tool flow using tool delivery system in these FMS rather than part flow in conventional FMS. According to existing study, in FMS 20~30 percent of the total management cost is the cost related with tools and it is possible to reduce the tool inventory by 40 percent using efficient tool allocation. In this study, in FMS under dynamic tool allocation strategy, a new method of part release considering tool flow at the stage of part release is proposed. In order to prove the efficiency of the proposed part release it is compared with other part release through simulation experiments. Performance measures in these experiments are the throughput and the number of tardy parts.