• Journal of KIISE:Computer Systems and Theory
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• v.32 no.7
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• pp.349-358
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• 2005

False sharing is a result of co-location of unrelated data in the same unit of memory coherency, and is one source of unnecessary overhead being of no help to keep the memory coherency in multiprocessor systems. Moreover. the damage caused by false sharing becomes large in proportion to the granularity of memory coherency. To reduce false sharing in a page-based DSM system, it is necessary to allocate unrelated data objects that have different access patterns into the separate shared pages. In this paper we propose call-site tracing-based shared memory allocator. shortly CSTallocator. CSTallocator expects that the data objects requested from the different call-sites may have different access patterns in the future. So CSTailocator places each data object requested from the different call-sites into the separate shared pages, and consequently data objects that have the same call-site are likely to get together into the same shared pages. We use execution-driven simulation of real parallel applications to evaluate the effectiveness of our CSTallocator. Our observations show that by using CSTallocator a considerable amount of false sharing misses can be additionally reduced in comparison with the existing techniques.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.374-388
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• 2016

In Jeju-Do, there is the 1100 Road, 516 Road, and Bijarimro, which are typical mountain sight-seeing roads in Jeju. These roads are local roads that have been the location for many traffic accidents. This study focused on these roads, categorized the type of traffic accident and analyzed the accident characteristics. The major accident factors were analyzed through trip AHP analysis, Comparative analysis of the velocity distribution and the factors affecting traffic accidents were analyzed. Tourists took many trips on these roads. The mixing rate of the rental cars was 36.70%~71.60% in 1100 road and Bijarimro. Currently, these local roads are regulated by a speed limit of 60km/h. However, it might be necessary to reduce the speed limit to 40km/h considering the geometric line form of the road and the climate in these areas. The speed limit of more than 40km/h is found 87.0% on 516 Roads, 88.57% on 1100 roads, and 93.1% on Bjarimro, In these roads, the speed ratio is higher as described above. Therefore, these roads have been found to have a higher risk of traffic accidents by overspeeding driving. The overspeed driving ratio of these roads was 87.0%~93.1%, The overspeed driving enforcement method at one spot has only the effect of reducing the speed at that enforcement place; the effect cannot be expected for the other places or sections. It is necessary to introduce a section overspeed driving enforcement system utilizing the average velocity in these areas to prevent traffic accidents.

• The Korean Journal of Quaternary Research
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• v.20 no.1 s.26
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• pp.9-27
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• 2006

The East Asian (China, Korea and Japan) summer monsoon precipitation and its variability are examined from the outputs of the 22 coupled climate models performing coordinated experiments leading to the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) following the multi-model ensemble (MME) technique. Results are based on averages of all the available models. The shape of the annual cycle with maximum during the summer monsoon period is simulated by the coupled climate models. However, models fail to simulate the minimum peak in July which is associated with northward shifts of the Meiyu-Changma-Baiu precipitation band. The MME precipitation pattern is able to capture the spatial distribution of rainfall associated with the location of the north Pacific subtropical high and the Meiyu-Changma-Baiu frontal zone. However precipitation over the east coast of China, Korea-Japan peninsular and the adjoining oceanic regions is underestimated. Future projections to the radiative forcing of doubled $CO_2$ scenario are examined. The MME reveals an increase in precipitation varying from 5 to 10 %, with an average of 7.8 % over the East Asian region at the time of $CO_2$ doubling. However the increases are statistically significant only over the Korea-Japan peninsula and the adjoining north China region. The increase in precipitation may be attributed to the projected intensification of the subtropical high, and thus the associated influx of moist air from the Pacific to inland. The projected changes in the amount of precipitation are directly proportional to the changes in the strength of the subtropical high. Further a possible increase in the length of the summer monsoon precipitation period from late spring through early autumn is suggested.

• Journal of the Korean association of regional geographers
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• v.7 no.2
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• pp.35-54
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• 2001

The construction of Daedeok Science Town, located in Yuseong ward of Daejeon metropolitan city, began in the early 1970s. It started out as a national project to form an agglomeration of the major central government research institutions. Since that time Daedeok Science Town has also attracted private research institutions, mainly during the 1900s. This study geographically analyzes this research institutions to clarify the regional identity of Daedeok Science Town through an integrated approach of existing new regional geography approach, which is characteristics of labour market as the regional pattern of its laborers' residences, spatial labour division, its research network with other institutions, and networks of university, research institution, and corporations, through the spatial spread of intellectual right of property and through network of technology business incubator relationship with spin offs which is appeared to spatial interaction. The results of the study are as follows: First of all, Daedeok Science Town was not only self-sustenance with marketing garden of agricultural regions in the suburb of Daejeon city but also was consign of agricultural products to Daejeon city before 1972. Since that time, the identity of Daedeok Science town has been formed by externally factors of the science development, by the local decentralization of population and public offices in Seoul metropolitan area in terms of the world economy system, and by the internally accessibility maximization of the central location in Korea between 1992 and 1999. On the part of Daedeok Science Town it has some merits of in-migration from nation-wide, and of mother city's Daejeon. Lastly at the period of the venture business beginning after 1999, the role of institution, developing the existing high technology, made great contribution to an attraction of ventures business to here in need of high technology industry growth, including knowledge-based industry in the informated society. On these bases, Daedeok Science Town seems to grow spontaneously as a science park.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.73-80
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• 2008

An hydraulic experiment was carried out in an open channel flume in order to improve the technique of designing shape of the sluice used for tidal power generation, which greatly affects the economical efficiency of the construction of a tidal power plant. To predict the influence of change in the major design parameters relating to the sluice shape on the water discharge capability of the sluice, it was necessary to perform a precise experiment that is discriminated to previous feasibility studies or design projects. For this purpose, by installing various flow straighteners and rectifying structures inside the water supply system and the rectifying tank, the flow in the flume was stabilized as tranquil as possible. In addition, the measuring instruments and the location of installing them were carefully determined so as to minimize the errors intervened during the measurement of water discharge and water level. The method of estimating head difference between upstream and downstream of the sluice was also developed by taking account of the head loss due to the friction at the bottom and side walls in the flume.

• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.2
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• pp.23-37
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• 1985

This studies were carried out to get characteristics of frequency distribution, probable flood flows according to the return periods, and the correlation between return periods and those length of records affect the Risk of failure in the annual maximum series of the main river systems in Korea. Especially, Risk analysis according to the levels were emphasized in relation to the design frequency factors for the different watersheds. Twelve watersheds along Han, Geum, Nak Dong, Yeong San and Seom Jin river basin were selected as studying basins. The results were analyzed and summarized as follows. 1. Type 1 extremal distribution was newly confirmed as a good fitted distribution at selected watersheds along Geum and Yeong San river basin. Three parameter lognormal Seom Jin river basin. Consequently, characteristics of frequency distribution for the extreme value series could be changed in connection with the watershed location even the same river system judging from the results so far obtained by author. 2. Evaluation of parameters for Type 1 extremal and three parameter lognormal distribution based on the method of moment by using an electronic computer. 3. Formulas for the probable flood flows were derived for the three parameter lognormal and Type 1 extremal distribution. 4. Equations for the risk to failure could be simplified as $\frac{n}{N+n}$ and $\frac{n}{T}$ under the condition of non-parametric method and the longer return period than the life of project, respectively. 5. Formulas for the return periods in relation to frequency factors were derived by the least square method for the three parameter lognormal and Type 1 extremal distribution. 6. The more the length of records, the lesser the risk of failure, and it was appeared that the risk of failure was increasing in propotion to the length of return periods even same length of records. 7. Empirical formulas for design frequency factors were derived from under the condition of the return periods identify with the life of Hydraulic structure in relation to the risk level. 8. Design frequency factor was appeared to be increased in propotion to the return periods while it is in inverse proportion to the levels of the risk of failure. 9. Derivation of design flood including the risk of failure could be accomplished by using of emprical formulas for the design frequency factor for each watershed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2689-2696
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• 2015

Radioactive isotopes which are manufactured using a cyclotron in a radioisotope used for radiation diagnosis is affected by the production yield according to size and shape of the beam and beam uniform degree from irradiated location when the proton beam investigated the target by cyclotron. Therefore, in this paper developed the BPM(Beam Profile Monitor) device capable of measuring the beam cross-section at the cyclotron beam line. It was configured so as to be able to remote control the BPM device in LabView and used the BPM program it was to be able to easily monitor and display to analyze the graph of two-dimensional graph and a three-dimensional beam distribution numerical information of the beam obtained while scanning the tungsten wire to the X and Y axis. The time it takes to measure the beam can be confirmed 37seconds when step motor driving speed was 2000pps. Through a beam readjusted based on the measured beam distribution information by optimizing the beam distribution it can be made to maximize the RI production yield and contribute supply stabilization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.246-250
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• 2006

The objective of this research was to investigate the way information is used by pedestrians in underground space. Furthermore, we wanted to know how pedestrians utilize information from signage of signs by pedestrians. Thus, we conducted an investigation on the pedestrians' walking behavior in Fukuoka City, Tenjin underground shopping centers, and 1) checked routes taken by the subjects; and 2) categorized the signs that were observed, the pedestrians' movement patterns, the way information from signage isused by the pedestrians, the signs' locations, the relationship between the spaces, the heights of the signs and the types of signs offering directions. The results showed that there is a need to solve certain problems related to the locations of the signs and the walking behaviors of the subjects. To solve the problems exhibited by the subjects' walking behaviors, we came up with a variety of guidance information that could be used. The contents of the guidance information differ depending on the specified heights for the placement of signs and the information used depending on the location. The results also showed that the continuity between places needs to be shown more effectively by the guidance system, and that too many signs are positioned in places where the frequency of use is low.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.7
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• pp.345-350
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• 2016

This research suggests the keyword filtering about disaster and the method of detecting area in real-time event detecting system by analyzing contents of twitter. The diffusion of smart-mobile has lead to a fast spread of SNS and nowadays, various researches based on studying SNS are being processed. Among SNS, the twitter has a characteristic of fast diffusion since it is written in 140 words of short paragraph. Therefore, the tweets that are written by twitter users are able to perform a role of sensor. By using these features the research has been constructed which detects the events that have been occurred. However, people became reluctant to open their information of location because it is reported that private information leakage are increasing. Also, problems associated with accuracy are occurred in process of analyzing the tweet contents that do not follow the spelling rule. Therefore, additional designing keyword filtering and the method of area detection on detecting real-time event process were required in order to develop the accuracy. This research suggests the method of keyword filtering about disaster and two methods of detecting area. One is the method of removing area noise which removes the noise that occurred in the local name words. And the other one is the method of determinating the area which confirms local name words by using landmarks. By applying the method of keyword filtering about disaster and two methods of detecting area, the accuracy has improved. It has improved 49% to 78% by using the method of removing area noise and the other accuracy has improved 49% to 89% by using the method of determinating the area.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.17-28
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• 2010

A climbing lane is installed to separate low-speed traffic from high-speed traffic if drastic traffic capacity reduction is expected due to a large number of vehicles that slow down in the upward section. Existing studies on climbing lanes have focused on the designation, location of starting and ending points, and installation method of climbing lane with regard to road design standards. However, in terms of traffic operation, it was known that the climbing lanes cause traffic congestion due to the increase of traffic volumes. In this regard, this study aims to establish traffic operational guidance as to how much effects temporary closure of climbing lanes can have on traffic improvement according to the volume-capacity ratio, grade, and composition of trucks. A test section of simulated climbing lane was selected in Nakdong JC bound for Masan(136.9K~133.3K, 3.6km, 3.7%) on Jungbunaeryuk expressway to conduct VISSIM analyses, microscopic traffic simulation based on such control variables as traffic volume(v/c), grade and the trucks ratio. As a result of the analyses, it has been found that v/c and the ratio of trucks are the key variables for efficient traffic management of climbing lanes in order to relieve traffic congestion via climbing lane. If ratio of trucks are more than 50% and when v/c would be 0.8, both climbing lane would be closed and non-operated regardless of grade and ratio of trucks when v/c is 1.0. With the increased traffic due to a five-day work week system, continued peak hours during the weekday, increased and various patterns of congestion on expressway, this study would be expected to contribute to facilitating researches on flexible operational standards for road facilities.