• Journal of the Society of Naval Architects of Korea
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• v.54 no.5
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• pp.421-429
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• 2017

It is very important to manage the position of the blocks in the shipyard where the work is completed, or the blocks need to be moved for the next process operation. The moving distance of the block increases according to the position of the block stockyard. As the travel distance increases, the number of trips and travel distance of the transporter increases, which causes a great deal of operation cost. Currently, the selection of the block position in the shipyard is based on the know-how of picking up a transporter worker by the production schedule of the block, and the location where the block is to be placed is determined according to the situation in the stockyard. The know-how to select the position of the block is the result of optimizing the position of the block in the shipyard for a long time. In this study, we used the accumulated data as a result of the operation of the yard in the shipyard and tried to select the location of blocks by learning it. Decision tree learning algorithm was used for learning, and a prototype was developed using it. Finally, we prove the possibility of selecting a block stockyard through this algorithm.

• Human Ecology Research
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• v.53 no.1
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• pp.49-66
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• 2015

This study analyzes the effects of women's labour force participation and work-family reconciliation support on life-cycle fertility in Korea. The analysis is based on the longitudinal data from Korean Labour and Income Panel Study (KLIPS), which include the available information on life-cycle fertility and employment history. Employing a dynamic model of fertility, we estimated the life-cycle fertility of all the 15-49 years old women considered in this study by using a duration model. The major results of this study were as follows: First, women's labour force participation had a negative effect on the first birth, second birth, and all births (transition to births starting at different parities). Women's employment tended to lengthen the interval between births. Second, the availability of maternal leave had a positive effect on the first birth and all births for working women. Providing maternal leave to working women decreased the opportunity cost of childbearing and in turn, reduced the interbirth interval of women. However, the availability of parental leave had no significant effect on the births of working women. Third, the financial support for childcare had a positive effect on the first birth and all births. The economic support for childcare led to the reduction in the interbirth interval of women by increasing the probability of births. The use of a childcare center for the first child, which substitutes for the time that women needed to take care of their children, classified as time-intensive consumption goods, did not have any effect on the second birth. Fourth, the part-time employment of women had a positive effect on the second birth. A flexible working time schedule tended to decrease the interval between the first and the second births.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.49-56
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• 2010

A competitive construction project must address factors such as cost, performance, aesthetics, schedule and quality. The importance of these factors will vary from project to project and from market to market. Productivity is becoming an ever-more important factor in the acquisition of a project. As the technology or aesthetics of a product matures or stabilizes, and the competitive playing field levels, competition is increasingly based on time. Recently, the construction industry has been depressed due to difficult market circumstances. At this time in particular, construction companies are striving to rationalize their management, both in their planning offices and in the field. In this study, we present a method of calculating a reasonable duration for reinforced form work. We did this by first developing a question for field workers, then sampling form workers based the question. Second, we employed a work analysis method to analyze worker"s work-methods and Time. Then, using the result of this analysis, we measured the Productivity of form work. This measure can be used as basic data to determine the appropriate duration of form work.

• Land and Housing Review
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• v.1 no.1
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• pp.9-17
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• 2010

Due to the variety of processes that are mainly influenced by the modification of law and regulations, it is difficult to propose a formal procedure of urban renewal projects. In addition, conflicts among various participants and stake-holders have made urban renewal difficult to manage. Needs for new systems to support management of this type of projects have been raised. This system should enable users to manage program aspects as well as projects given that the urban renewal consists of several projects. According to analysis of current context, the requirements of the system are classified as follows: a method to create flexible systems to cope with various process; functions to provide data on cost and schedule; user-friendly visualized tools enhancing understand of non-experts or less-experienced participants. This paper summarizes the background, requirements, concept and model of the system. Currently, prototype systems have been developed. Regarding outputs presented so far, potential benefits of the system are presented as well.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.30-38
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• 2014

Achieving high productivity and constructability are very important issues in construction industry. Study on constructability have been conducted actively, and many researches referred that improving constructability can enhance cost, quality, schedule, productivity and so on. However, there are lack of quantitative analysis, since most studies have proved correlation between productivity and constructability using questionaries and by case studies. Also, researches are mostly about specific detail scope of work to improve constructability, thus it is hard to apply constructability factors on various work in construction. In this paper, will deduct general factors affecting on constructability and evaluate effects of factors affecting on each work. Furthermore this paper will verify impact of factors affecting on productivity by multi regression anlaysis using actual data sets of high-rise building construction site.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.77-86
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• 2019

Due to the increasing demand for and complexity of plant construction projects, unpredictable risk factors are on the consequent increase. For that reason, the quantitative risk analysis is being called for, in order for the development of a risk assessment model using risk indicators for the plant construction projects. This study used the claim payout data collected at a global insurance company to reflect the actual financial losses in plant construction projects as dependent variables in the risk assessment model. In terms of independent variables, the geographic information, i. e., landform, and the construction information including test-run, schedule rate, total cost and duration are adopted. In addition, this study suggests that the regression model containing such independent variables that are statistically significant can be applied to as a foundational guideline for the plant construction project risk analysis during the phase of construction and commissioning.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.188-198
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• 2013

In order to increase its performance, NAND flash memory-based storage is composed of data buses that are shared by a number of flash memories and uses a parallel technique that can carry out multiple flash memory operations simultaneously. Since the storage performance is strongly influenced by the performance of each data bus, it is important to improve the utilization of the bus by ensuring effective scheduling of operations by the storage controller. However, this is difficult because of dynamic changes in buses due to the unique characteristics of each operation with different timing, cost, and usage by each bus. Furthermore, the scheduling technique for increasing bus utilization may cause unanticipated operation delay and wastage of storage resource. In this study, we suggest various dynamic operation scheduling techniques that consider data bus performance and storage resource efficiency. The proposed techniques divide each operation into three different stages and schedule each stage depending on the characteristics of the operation and the dynamic status of the data bus. We applied the suggested techniques to the controller and verified them on the FPGA platform, and found that program operation decreased by 1.9% in comparison to that achieved by a static scheduling technique, and bus utilization and throughput was approximately 4-7% and 4-19% higher, respectively.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.11
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• pp.357-366
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• 2020

As the proportion and complexity of software embedded in aircraft increase, risk factors such as mission failure, function failure and performance failure due to software errors also increase. In the mission-critical software systems such as aircraft software, managing requirement traceability is essential to maintain the software systems with minimal period and cost. However, the development company is not accurately complying with the guideline for managing requirement traceability due to various reasons such as development cost and schedule. Therefore, it is not easy to systematically establish and maintain requirement traceability. In the paper, we analyze actual test cases of aviation software systems from the viewpoint of requirements traceability in order to learn if there are failure cases of test cases due to the absence of systematic traceability management activities. We also check the risks associated with the failure cases according to the type and severity of the cases. As a result of analyzing a total of 7 aircraft-mounted software, failure cases could be divided into three types: omission of requirements, lack of connection between requirements and test procedures, and omission of test procedures. There were a total of 18 failure cases, 6 for each type. The numbers of high, middle and low risks were 1, 13 and 4, respectively, where the number of middle risks is largest.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.835-844
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• 2002

The number of channels available to a video server is limited since the number of channels a video server can support is determined by its communication bandwidth. Several approaches such as batching, piggybacking and patching have been proposed to reduce I/O demand on the video server by sharing multicast data. Patching has been shown to be efficient in the matter of the cost for VOD systems. Unlike conventional multicast techniques, patching is a dynamic multicast scheme which enables a new request to join an ongoing multicast. In addition, true VOD can be achieved since a new request can be served immediately without having to wait for the next multicast. In this paper. we propose two types of channel reservation patching algorithm : a fixed channel reservation patching and a variable channel reservation patching. To immediately schedule the requests for popular videos, these algorithms reserve the channels of video server for the fixed number of popular videos or for the variable number of popular videos which is determined dynamically according to the load of video server. The performance of the proposed algorithms is evaluated through simulations, and compared with that of simple patching. Our performance measures are average defection rate, average latency, service fairness and the amount of buffered data according to video server loads. Simulation results show that the proposed channel reservation patching algorithms provide better performance compared to simple patching algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.237-249
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• 2017

This research aims to gain a better understanding of college students' thoughts on what factors make them happy and contribute to enhancing their happiness. We focused on the relationship between their self-assessed happiness and various factors affecting happiness, such as their socio-economic status, relationships with others, future orientation, and daily activities. Survey data were collected from October, 2014 to December, 2014 at a South Korean University. The final total number of respondents was 474 from 500 distributed questionnaires, after excluding 26 responses with missing values and unanswered items. The response was comprised of 247 male students, and 227 female students, and of 268 freshmen, 145 sophomores, 35 juniors, and 26 senior students. Factors that were statistically significant were gender, year, average cost of leisure, appearance satisfaction, conversation hour with parents, having girlfriend/boyfriend, sexual experience, number of friends, satisfaction with major, Grade Point Average (GPA), studying hours, time for self-improvement, reading hours, use of smart phone hours, number of daily meals, exercise hour, schedule management and future goal setting. This research was conducted utilizing only data from one university and so it may not be appropriate to generalize the results. Moreover, some of the variables are not in line with previous studies on happiness. Some other mediating variables may exist. Therefore, following research should be conducted.