• 산업공학
• /
• 제11권3호
• /
• pp.103-114
• /
• 1998

This paper suggests a computer software system which generates standard times for assembly products. The system called "computer aided logical system for standard times(CALS4ST)" incorporates a modified bill of materials, BOM4ST(BOM for standard time) to deal with auxiliary operations which are not directly related to parts and assemblies listed in the standard BOM. Typical examples of the operations include inspection, adjustment, and repairing works to be done before or after assembly operations. Once standard time data bases for both the part assembly operations and the auxiliary operations are set up, the system relates the BOM4ST to the standard time data bases so as to calculate the standard time for a assembly part concerned. According to the structure of parts and auxiliary operations in the BOM4ST, their standard times stored in the data bases are to be sequentially added up considering the specified assembly-operation characteristics. To illustrate the feasibility of the system, the case study of L company is provided.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
• /
• pp.507-512
• /
• 2002

In road pavements, it is known that cement concrete pavement has superior durability. But in repairing pavement, cement concrete pavement is not usually applied because of the length of time while the road is interrupted when using Ordinary and Rapid-hardening Portland Cement. And Super High Early Strength Cement and Ultra Super High Early Strength Cement are not favorable for ready mixed concrete because of rapid setting time, high slump loss and other restrictions. We developed special cement developing 1 day strength of over 30.0N/$mm^2$ to open the road within 1 day and workable time is maintained over 1 hour so that it can be used as ready mixed concrete. We performed experimental overlay construction with concrete and evaluated the properties of the fresh and hardened concrete. The flexural strength was over 5.0N/$mm^2$ and the compressive strength was over 30N/$mm^2$ at 1 day. So it is thought that the road can be open to traffic within 1 day after placement.

• Industrial Engineering and Management Systems
• /
• 제12권4호
• /
• pp.306-316
• /
• 2013

The semiconductor industry has grown rapidly, and subsequently production planning problems have raised many important research issues. The reentrant flow-shop (RFS) scheduling problem with time windows constraint for harddisk devices (HDD) manufacturing is one such problem of the expanded semiconductor industry. The RFS scheduling problem with the objective of minimizing the makespan of jobs is considered. Meeting this objective is directly related to maximizing the system throughput which is the most important of HDD industry requirements. Moreover, most manufacturing systems have to handle the quality of semiconductor material. The time windows constraint in the manufacturing system must then be considered. In this paper, we propose a hybrid genetic algorithm (HGA) for improving chromosomes/offspring by checking and repairing time window constraint and improving offspring by left-shift routines as a local search algorithm to solve effectively the RFS scheduling problem with time windows constraint. Numerical experiments on several problems show that the proposed HGA approach has higher search capability to improve quality of solutions.

• 한국도로학회논문집
• /
• 제15권6호
• /
• pp.49-60
• /
• 2013

PURPOSES : The evaluation of the pavement condition of the asphalt concrete pavement of No. 2 runway of Inchon International Airport through PMS, a supporting system for making a decision of pavement, maintenance and repair, was made, and the proper time for repair according to the PCI reduction rate was suggested. METHODS : By comparing and analyzing the evaluation results of pavements built in 2009, 2010, 2011, PCI change in each facility (No. 2 runway, C parallel taxiway, connection taxiway) was calculated. By applying the calculated change to PCI deduction rate model, the pavement condition of the target sections was estimated, and then the necessary section and time for repair were chosen. RESULTS : After careful consideration of the time for pavement and maintenance, based on the result of PCI prediction, it was estimated that the southern takeoff and landing section of No. 2 runway was required to be repaired in 2012; connection taxiway in 2013; and C parallel taxiway in 2014; however, the section which is the main moving route of connection taxiway and C parallel taxiway was needed to be repaired in 2012. CONCLUSIONS : For maintenance and repair of airport pavements, the optimal alternative should be chosen by considering economics and operability, via examining the time for repair and the aspect of management all together on the basis of this study.

• 제어로봇시스템학회논문지
• /
• 제22권5호
• /
• pp.374-381
• /
• 2016

The sealing technique is widely used for repairing the cracks on the surface of concrete and preventing their expansion in the future. However, it is difficult to ensure the safety of the workers when sealing large structures in inconvenient working environments. This paper presents the development of a sealing robot system to seal various shapes of concrete surface in rough conditions for a long time. If the robot can maintain the desired contact force, the cracks can be completely sealed. An impedance force tracking controller with slope estimator is proposed to calculate the surface slope in real time using the robot position. It predicts the next point in order to prevent the robot from disengaging from the contact surface owing to quick slope changes. The proposed method has been verified by experimental results.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.629-636
• /
• 2003

The purpose of this study is localization of safety relief valves for Nuclear Service through technical development with overall design, fabrication, inspection, capacity certification test and functional qualification test of safety relief valves in accordance with ASME Section III and KEPIC Code. Safety relief valve is the important equipment used to protect the pressure vessel, the steam generator and the other pressure facility from overpressure by discharging the operating medium when the pressure of system is reaching the design pressure of the system. But we're depending on technology of the other country up to the present time. Because we don‘ have our own technologies, we have been spent the great time and money on installing and repairing safety relief valve at nuclear power plant. Therefore we have to achieve the development of safety relief valves for Nuclear Service with our own technologies.

• Structural Monitoring and Maintenance
• /
• 제1권3호
• /
• pp.323-338
• /
• 2014

In this study a new innovative method of earthquake-resistant strengthening of reinforced concrete structures is presented for the first time. Strengthening according to this new method consists of the construction of steel fiber ultra-high-strength concrete jackets without conventional reinforcement which is usually applied in the construction of conventional reinforced concrete jackets. An innovative solution is proposed also for the first time that ensures a satisfactory seismic performance of existing reinforced concrete structures, strengthened by using composite materials. The weak point of the use of such materials in repairing and strengthening of old R/C structures is the area of beam-column joints. According to the proposed solution, the joints can be strengthened with a steel fiber ultra-high-strength concrete jacket, while strengthening of columns can be achieved by using CFRPs. The experimental results showed that the performance of the subassemblage strengthened with the proposed mixed solution was much better than that of the subassemblage retrofitted completely with CFRPs.

• 가정과삶의질연구
• /
• 제19권2호
• /
• pp.111-127
• /
• 2001

The purposes of this study were to investigate the relationships between individuals characteristics (socio-economic status, time pressures, resources related with implementing housework), attitudes toward goods characteristics, and the level of market goods substitution of housework in the domain of foods and clothes. For empirical analysis, the data of the study was collected from 572 married women living in Seoul. Covariance structure analysis were employed for data analysis, using LISREL. The major findings were as follows: 1) Individuals characteristics, attitudes toward market goods characteristics, and the level of goods substitution of housework had causal relationships. 2) Generally, wifes age and resources related with implementing housework were negative predictors of the level of market goods substitution of housework and wifes education, income, time pressures, attitudes toward characteristics of market goods were positive predictors. Wifes employment was a constraint of Korean traditional sauce, clothes repairing service and laundry service purchases, but a facilitator of the level of dining-out.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
• /
• pp.492-500
• /
• 2004

The purpose of this study is localization of safety relief valves fur Nuclear Service through technical development with overall design, fabrication, inspection, capacity certification test and functional qualification test of safety relief valves in accordance with KEPIC MN Code(or ASME Sec.III ). The safely relief valve is the important equipment used to protect the pressure vessel, the steam generator and the other pressure facility from overpressure by discharging the operating medium when the pressure of system is reaching the design pressure of the system. But we're depending on technology of the other country up to the present time. Because we don't have our own technologies, we have been spent the great time and money on installing and repairing safety relief valve at nuclear power plant. Therefore we have to achieve the development of safety relief valves for Nuclear Service with our own technologies.

• 한국시뮬레이션학회논문지
• /
• 제11권3호
• /
• pp.49-58
• /
• 2002

It takes 2 or 3 months to manufacture memory device. Defect has to exist owing to hundreds of processes. If there are too many defects, the memory has to be rejected. But if there are a few defects, it will be more efficient and cost reducing for the company to use it by repairing. Therefore, laser-repair process is needed for such a reason and redundancy analysis is needed to establish correct target of laser-repair process. The equipment development company had provided the redundancy analysis and each development company had developed and provided separately. So, to analyze the similar type of defects, redundancy analysis time can be very different by the manufacture. The purpose of this research is to strengthen the competitive price and to apply correlation concept in business for reducing the redundancy analysis time to repair the defects