• Structural Engineering and Mechanics
• /
• v.20 no.5
• /
• pp.589-608
• /
• 2005

There is a growing need for the development and implementation of new methods for the rapid and cost-effective rehabilitation of deteriorating steel structural components to offset the drawbacks related to welding and/or bolting in the field. Carbon fiber reinforced polymer (CFRP) composites provide a potential alternative as externally bonded patches for strengthening and repair of metallic structural members for building and bridge systems. This paper describes results of an investigation of tensile and fatigue response of steel/CFRP joints simulating scenarios of strengthening and crack-patching. It is shown that appropriately designed schemes, even when fabricated with levels of inaccuracy as could be expected in the field, can provide significant strain relief and load transfer capability. A simplified elasto-plastic closed form solution for stress analysis is presented, and validated experimentally. It is shown that the bond development length remains constant in the linear range, whereas it increases as the adhesive is deformed plastically. Fatigue resistance is shown to be at least comparable with the requirements for welded cover plates without attendant decreases in stiffness and strength.

• The Journal of the Korea Contents Association
• /
• v.10 no.11
• /
• pp.38-47
• /
• 2010

DMX512 protocol controls a lighting system for outdoor lightings and stage lightings. But lighting systems using DMX512 protocol based wired needs expensive cost in installation, maintain, repair. And it has restrictions about control channel numbers and its ranges. Also, it needs additional equipments for the control of lighting systems which installed on wide area. In this paper, we propose wireless control technique and a ZDMX module for lighting systems on wide area based on DMX512 protocol. Our technique solves problems of DMX512 protocol, and it can control lighting systems on wide area effectively. We developments the LED lighting system using ZDMX modules and we have confirmed the suitability of our technique for real environment.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.79-84
• /
• 1992

Path planning is an important task for optimal motion of a robot in structured or unstructured environment. The goal of this paper is to plan the optimal collision-free path in 3D, when a robot is navigated to pick up some tools or to repair some parts from various locations. To accomplish the goal, the Path Coordinator is proposed to have the capabilities of an obstacle avoidance strategy and a traveling salesman problem strategy (TSP). The obstacle avoidance strategy is to plan the shortest collision-free path between each pair of n locations in 2D or in 3D. The TSP strategy is to compute a minimal system cost of a tour that is defined as a closed path navigating each location exactly once. The TSP strategy can be implemented by the Hopfield Network. The obstacle avoidance strategy in 2D can be implemented by the VGraph Algorithm. However, the VGraph Algorithm is not useful in 3D, because it can't compute the global optimality in 3D. Thus, the Path Coordinator is used to solve this problem, having the capabilities of selecting the optimal edges by the modified Genetic Algorithm and computing the optimal nodes along the optimal edges by the Recursive Compensation Algorithm.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1121-1128
• /
• 2007

Subway routes $1{\sim}4$ were constructed in gravel roadbed track structure in consideration of the technological capabilities, construction cost and duration at the time of the initial construction. As such, 224.8km, approximately 81.2% of entire length, of total length of railway track at 276.9km was constructed on gravel roadbed. However, improvement of gravel roadbed to concreted roadbed began in 1998 due to problems including frequent repair works and limited time application for such works caused by occurrence of tract distortion during operation as well as lowering of roadbed functions and generation of dust caused by frictional power, impact absorption capabilities, abrasion and crushing of gravel on roadbed. Currently, this improvement is continuing with target of converting entire route into concreted roadbed structure. Therefore, this Study modifies formula for setting cant, analyze the correlation between wearing of rail side of the curvature and cant insufficiency following increasing of the running speed of the train, and to present the directions for fundamental review for adjustment of cant insufficiencies at the time of improvement of gravel roadbed to concreted roadbed that is being implemented on the operational tracks of the railway trains.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1196-1202
• /
• 2007

In construction of high speed railway, the fan shape is limited to achieve reduction of required travel time and concrete railway which has structural stability and induces small maintenance cost with allowable ground settlement is recently applied. So construction of concrete railway on soft ground in which considerable ground settlement occurs increases and settlement management in soft ground section is required. Field monitoring on ground movement and integrated geotechnical information system which manages construction, design, and field monitoring data are essential for settlement management of concrete railway subgrade. Site investigation data are also required due to future repair work. Therefore in this study, integrated geotechnical information system for construction and maintenance of concrete railway is developed. The developed system consists of a database and an application program. The database contains site investigation, construction, design, and field monitoring data throughout a railway. Application program performs various functions on managing and utilizing information in the database with graphic visualization of output. And by providing integrating information with comprehensible visual displays, the applicability and effectiveness of the developed system for construction and maintenance management were confirmed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.33 no.3
• /
• pp.199-207
• /
• 2010

In this paper considered is the provisioning quantity determination problem of consumable concurrent spare parts (CSP) of a new equipment system to minimize the procurement cost under the operational availability constraint. When a part fails, repair of the failed part is impossible and the part is replaced and cannibalization is allowed. The failure of a part is assumed to follow a Poisson process and the operational availability in CSP is defined. The solution procedure consists of two parts. Firstly, a heuristic algorithm is developed under the assumption that the failure rate is constant during the CSP period. Secondly, proposed is a simulation search procedure which improves the heuristic solution to the near optimal solution in a reasonable amount of time. An illustrative example is shown to explain the solution procedure.

• Carbon letters
• /
• v.9 no.4
• /
• pp.324-339
• /
• 2008

The principal aims of the review paper are (1) to establish broad overview information, both qualitative and quantitative, relating to the world market for polyacrylonitrile (PAN) or pitch-based carbon fibers; and (2) to generate an effective analysis and break down of consumption by process route and eventual end-use. The review paper also designed specifically to provide subscribers with an accurate, independent, and realistic assessment of the current status and future perspective of the market for carbon fibers in the world. The world market for carbon fibers continues to grow rapidly, fuelled by new industrial end uses, such as sport and leisure goods, aerospace, automotive applications, civil engineering and infrastructure repair, and immerging applications in energy generation. Demands for properties of carbon fibers used in those applications include many things such as strength, toughness, fatigue property, corrosion resistance, heat resistance, etc., and these become to be higher level. On the other hand, demands for manufacturing technologies of carbon fibers become to be difficult with these demands for properties, and these are wide variety such as high efficiencies, high qualities, many functions, labor saving, and low cost. In this review paper, thus, the recent carbon fibers corresponded to these needs, and its latest manufacturing technologies as well as market prospects are described.

• Journal of the Korean housing association
• /
• v.26 no.5
• /
• pp.113-121
• /
• 2015

Several housing improvement programs for low-income have done by Ministry of Health & Welfare, Ministry of Trade, Industry & Energy, Ministry of Security and Public Administration, Ministry of Environment, and Ministry of Land, infrastructure and Transport up to now. Each program practiced separately based on each agency's function and territory, but there are also negative opinion on beneficiary duplication, beneficiary omission, and the inefficient execution of the government budget. This study analyzes the housing improvement programs of each agency on the aspects of coordination, and suggests the integration system with coordination and delivery system. We selected 3 indexes such as similarity, integration effect and availability for integration system and analyzed the effects of integrated programs into one based on cost, repair effect and management. We proposed that the similar housing improvement programs of each agency should be coordinated for integration. But it is not easy to integrate similar programs into one program, therefore similar programs which support the house owner are needed to integrate into housing benefit except same beneficiary who owned own house.

• Journal of the Korean Institute of Gas
• /
• v.15 no.4
• /
• pp.1-6
• /
• 2011

Risk-based inspection (RBI) is a inspection technique suggesting inspection plan, such as inspection interval and inspection method, of the pressurized facilities based on its risk in the petrochemical, refinery and gas industries. Therefore, we can intensively and cost-effectively maintain, repair and manage the high-risk facilities through RBI technology. This paper reviews RBI technology, such as principle and implemental procedure of RBI, management of risks and facilities and return of investment through RBI, RBI technology at present and its application in domestic industries. In addition, some improvement directions of RBI are also proposed.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.7 no.5
• /
• pp.482-489
• /
• 2002

This paper studies the stand-alone photovoltaic system for the solar lighting lamp. The solar lighting lamp has PV modules, batteries, and charge & discharge system. The charge efficiency is improved for the control of each battery which is divided the charge from the discharge to change the structure of existing solar lighting lamp charge & discharge system. so, the charge and discharge times are reduced of 50% and the depth of discharge control can be controlled in the discharge cut off voltage. It can be effective of the battery use. If a battery is out of order, this system can be executed for a regular period. So we saved the repair cost and developed of system's stabilization. It Is possible to make economical effects to apply for solar lighting lamp used photovoltaic system.