• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1997-1998
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• 2006

In this paper, we propose a remote control system which is used by internet network system in the small water booster supply. So far, TMTC(Tele Metering Tele Control) has been used to control and monitor small water booster pump. But it is possible and easy to control and observe local booster panel with the rapid development of internet, This new system is to provide operators and managers with sufficient information and control in order to implement the operation in an efficient and economical way. This system consists of three parts that are controller, netpump server and netview client. Controller has a dual architecture. The motive for installing controller is the continuous production and supply of drinking water.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.141-144
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• 1997

This paper presents design automation system using API and parametric modeling of solid modeler, which is applied on axial fans for cooling towers. The design data including chord length and twist angle according to the fan length are given by design program, and API functions are applied to automate the modeling and assembly process of fan blade. The boss to connect fan and motor is designed with parametric design function provided by UG so as to be flexibly changed by the value of design parameters. The process of generating 2-D drafting for parts and an assembly is also automated. With developed system, the modeling time is reduced to 5 minutes even with unskilled operators.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.73-76
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• 2006

International Roaming is a kind of telecommunication service that enables subscribers use the same mobile number when they go abroad and access other service provider's network. International roaming call is made through three network parts-home (original service provider) network, intermediate network, and local (overseas service provider) network. It is not possible to monitor every section of whole roaming service network because service providers do not provide their network management information to other service providers. The limitation causes harsh problem when a service anomaly arises and operators have to confirm the reason of failure. To solve this problem, we propose a scheme that deduces roaming service status of each overseas service provider using internal network management information. SK telecom implemented a international roaming service management system based on the scheme using performance measurement of signaling points, roaming service nodes, and charging data from existing network management systems.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.45-45
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• 2000

This paper proposes a remote control system that combines computer network and an autonomous mobile robot. We control remotely an autonomous mobile robot with vision via the internet to guide it under unknown environments in the real time. The main feature of this system is that local operators need a World Wide Web browser and a computer connected to the internet communication network and so they can command the robot in a remote location through our Home Page. The hardware architecture of this system consists of an autonomous mobile robot, workstation, and local computers. The software architecture of this system includes the server part for communication between user and robot and the client part for the user interface and a robot control system. The server and client parts are developed using Java language which is suitable to internet application and supports multi-platform. Furthermore, this system offers an image compression method using motion JPEG concept which reduces large time delay that occurs in network during image transmission.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.139-147
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• 1999

Rapid Prototyping has made a drastic change in all industries which needs to reduce the time for the development of new products. Orientation and packing in rapid prototyping is considered as the most important factors to maximize the utilization of space in the build chamber and reduce build time. However, the decision of these parameter is mainly dependant on the operators's experience. This paper presents the methodology to find the optimal build layout considering an orientation and packing of multiple parts in SLS processing. Each part is represented as a voxel structure to deal with the inefficiency in a bounding box approach. Test results show that the adapted BL algorithm with a genetic algorithm(GA) can be applicable to a real industry.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.424-428
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• 2008

On processing of the shipbuilding, Various steel plates are used as the important material in many fields including the shell plate, a structure, etc. Therefore, the proper steel plate management system like a warehousing, pile, delivery is very important. Presently Operators manage the steel plate by using the software program, but they manage many parts manually, so many problems are generated on the steel plate check, management, and operator safety. In order to solve this problem, we developed Auto Steel-Plate Piling System. Also this system automatically manages and traces the steel-plate from warehousing to delivery.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.425-428
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• 2004

Flexible assembly line (FAL) is a production system that assembles various parts in unidirectional flow line with many constraints and manufacturing flexibilities. In this research we deal with a FAL balancing problem with the objective of minimizing the maximum workload allocated to the stations. However, almost all the existing researches do not appropriately consider various constraints due to the problem complexity. Therefore, this thesis addresses a balancing problem of FAL with many constraints and manufacturing flexibilities, unlike the previous researches. To solve this problem we use a genetic algorithm (GA). To apply GA to FAL, we suggest a genetic representation suitable for FAL balancing and devise evaluation method for individual's fitness and genetic operators specific to the problem, including efficient repair method for preserving solution feasibility. The experimental results are reported.

• International Journal of Quality Innovation
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• v.9 no.1
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• pp.22-40
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• 2008

Unnatural working postures usually cause musculoskeletal problems for workers in work field, especially in traditional industry. Many analysis and survey methodologies have been developed to identify unnatural postures and disorder risks in workplaces. The Ovako Working Posture Analyzing System (OWAS) and Nordic Musculoskeletal Questionnaire (NMQ) are the representative methods and applied widely. This study applied the both tools to investigate the work field of a manufacturing factory of the water heater's case. We divided the manufacturing process into nine workshops, took the pictures of working motions by DV camera and analyzed the postures on OWAS. From the OW AS results, we could identify the risks level of musculoskeletal symptoms as four Action Categories (AC). And from the comparison of OWAS and NMQ results, we could provide the suggestions to improve the working methods and environment. From the results of OWAS, we found that the operators' head/neck and back were above AC3 in some workshops. If the situation continued in long period, the operators might have the risk to get musculoskeletal symptoms. From the investigation of NMQ, we also found that the percentage of aches on neck, shoulders and lower back were higher than other parts of body. The correlation between aches and jobs was more than 75%. So we provided some suggestions to improve: work rotation and adjustment of work surface/height to fit in with Ergonomics. Then the risks of musculoskeletal symptoms would be reduced.

• Spatial Information Research
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• v.18 no.1
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• pp.77-87
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• 2010

Spatio-temporal join operators are essential to the management of spatio-temporal data such as moving objects. For example, the join operators are parts of processing to analyze movement of objects and search similar patterns of moving objects. Various studies on spatio-temporal join queries in outdoor space have been done. Recently with advance of indoor positioning techniques, location based services are required in indoor space as well as outdoor space. Nevertheless there is no one about processing of spatio-temporal join query in indoor space. In this paper, we introduce continuous spatio-temporal self-join queries in indoor space and propose a method of processing of the join queries over stream data of moving objects. The continuous spatio-temporal self-join query is to update the joined result set satisfying spatio-temporal predicates continuously. We assume that positions of moving objects are represented by symbols such as a room or corridor. This paper proposes a data structure, called Candidate Pairs Buffer, to filter and maintain massive stream data efficiently and we also investigate performance of proposed method in experimental study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1164-1183
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• 2019

The rapid development of cloud computing and high requirements of operators requires strong support from the underlying Data Center Networks. Therefore, the effectiveness of using resources in the data center networks becomes a point of concern for operators and material for research. In this paper, we discuss the online virtual-cluster provision problem for multiple tenants with an aim to decide when and where the virtual cluster should be placed in a data center network. Our objective is maximizing the total revenue for the data center networks under the constraints. In order to solve this problem, this paper divides it into two parts: online multi-tenancy scheduling and virtual cluster placement. The first part aims to determine the scheduling orders for the multiple tenants, and the second part aims to determine the locations of virtual machines. We first approach the problem by using the variational inequality model and discuss the existence of the optimal solution. After that, we prove that provisioning virtual clusters for a multi-tenant data center network that maximizes revenue is NP-hard. Due to the complexity of this problem, an efficient heuristic algorithm OMS (Online Multi-tenancy Scheduling) is proposed to solve the online multi-tenancy scheduling problem. We further explore the virtual cluster placement problem based on the OMS and propose a novel algorithm during the virtual machine placement. We evaluate our algorithms through a series of simulations, and the simulations results demonstrate that OMS can significantly increase the efficiency and total revenue for the data centers.