• Korean Journal of Construction Engineering and Management
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• v.10 no.1
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• pp.114-125
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• 2009

In this study, a design value analysis technique that considered stochastic LCC and stochastic performance evaluation was proposed, and by introducing the concept of reliability analysis, a decision making that secured reliability was supported. The results of this study, which was carried out according to the above objectives and methods, are summarized as follows: 1) The design value analysis procedures and value state function, improved in order to carry out a reliable analysis when evaluating alternate proposals that were extracted after the function definition was complete, were formalized, and in order to secure consistency and efficiency for value evaluation procedures, an evaluation index scheme was proposed; 2) Database collection and analysis were done for a bridge's LCC analysis. As for the collection scope of data, literature of previous research done on a bridge's LCC analysis was used as the basis for analysis, and for securing reliability regarding analysis results and dealing with uncertainty of collected data, the MCS technique was applied; 3) Weights and evaluation ranks for performance evaluation of each of the alternate proposals, as well as LCC analysis model, analysis period, discount rate, user expense, safety inspection and safety diagnosis expense conditions for LCC analysis were proposed. Lastly, a feasibility study was done and conclusion was made about "OO grand bridge and connecting road construction work execution design" project centered on value analysis execution case.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.103-111
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• 2017

In this study, the thermomechanical stress and fatigue analysis of a high voltage and high current (3,300 V/1200 A) insulated gate bipolar transistor (IGBT) module used for electric locomotive applications were performed under thermal cycling condition. Especially, the reliability of the copper wire and the ribbon wire were compared with that of the conventional aluminum wire. The copper wire showed three times higher stress than the aluminum wire. The ribbon type wire showed a higher stress than the circular type wire, and the copper ribbon wire showed the highest stress. The fatigue analysis results of the chip solder connecting the chip and the direct bond copper (DBC) indicated that the crack of the solder mainly occurred at the outer edge of the solder. In case of the circular wire, cracking of the solder occurred at 35,000 thermal cycles, and the crack area in the copper wire was larger than that of the aluminum wire. On the other hand, when the ribbon wire was used, the crack area was smaller than that of the circular wire. In case of the solder existing between DBC and base plate, the crack growth rate was similar regardless of the material and shape of the wire. However, cracking occurred earlier than chip solder, and more than half of the solder was failed at 40,000 cycles. Therefore, it is expected that the reliability of the solder between DBC and base plate would be worse than the chip solder.

• Management & Information Systems Review
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• v.32 no.4
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• pp.53-79
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• 2013

Social enterprises can be identified roughly as social purpose-oriented business ventures. They often fill the gaps left by governmental and commercial ventures in providing for certain vulnerable sectors of society. Though social enterprises often adopt market mechanisms in their organizational structures, their emphasis on particular social outcomes means that they intentionally pursue double/triple-bottom lines, thus distinguishing them from many traditional for-profit businesses. Among the Korean laborers, women have been hardest hit by the global economic crisis. As the movements have substantially been taken to strengthen women's economic activities in the recent years, many policies are formulated with these trends, connecting women's employment with social enterprises. This study focused on analyzing social enterprises to be friendly and to provide decent work to women. Data were collected from 491 social enterprises and 830 workers. The main results are as follows. First, the women's employment in social enterprises has accounted for a relatively high rate and the women's wage also is similar to men's one. Second, as for work conditions and types, most women have preferred irregular and non-managerial work. Thus, social enterprises have showed a positive response for the women's job opportunities, while social enterprises have had a negative one for enhancing the women's status at the labor market. In conclusion, social enterprises should institutionalize how to provide more stable working condition to women and to improve their's capacity.

• Korean Journal of Environment and Ecology
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• v.32 no.4
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• pp.355-372
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• 2018

The purpose of this study was to investigate the distribution of vascular plants in Mt. Daedeukbong. The study is significant because surveying the flora of old-growth forest in Mt. Daedeukbong is a way of understanding what kind of plant species exist in DMZ as the geographical characteristics of Mt. Daedeukbong adjacent to Korean DMZ have the role of a buffer zone connecting the DMZ and its southern region. We collected the vascular plants 7 times from May 2015 to May 2017 and found a total of 393 taxa consisting of 84 families, 245 genera, 341 species, 4 subspecies, 43 varieties and 5 forms. The observed rare plant species as designated by Korea Forest Service were 8 taxa, and the endemic species were 6 taxa. 44 taxa were listed as specific plant species based on phytogeographical in the investigated area. 23 taxa were recorded as naturalized plants, and the naturalized rate and urban index were 5.3% and 8.7%, respectively.

• Korean Journal of Environment and Ecology
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• v.31 no.1
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• pp.1-23
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• 2017

Gwangchiryeong, located adjacent to the Korean DMZ, is a mountain pass connecting Yang-Gu, Gangwon-do with In-je. It reaches a height of 800m (2,624ft) and stands on the flank of Mt. Daeam-san, which has an elevation of 1,304m (4,278ft). It is important to survey the flora of Gwangchiryeong in that not only the area encompassing the waterfall and the valley along with dense old-growth forest has various plant species but also it is a way to make out what kind of plant species exist in the DMZ due to the geographical characteristics of Gwangchiryeong adjacent to the Korean DMZ. Therefore, this study was conducted to elucidate the distribution of vascular plants and their value in Gwangchiryeong. The vascular plants that were collected 9 times from April 2014 to September 2015, and consisted of a total of 513 taxa: 88 families, 297 genera, 441 species, 4 subspecies, 62 varieties and 6 forms. Among those observed species, the rare plant species designated by Korea Forest Service were 22 taxa including Hanabusaya asiatica, Paeonia japonica, Saxifraga octopetala, etc. Endemic species were 22 taxa containing Cirsium setidens, Heloniopsis koreana, Salvia chanryoenica, etc. 18 taxa were recorded as naturalized plants and their naturalized rate and urban index were noted as 3.5% and 5.6%. Among the surveyed 513 taxa, edible, medicinal, pasturing, ornamental, timber, dye, fiber and industrial plants were 197 taxa, 154 taxa, 180 taxa, 49 taxa, 24 taxa, 8 taxa, 4 taxa and 3 taxa, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6397-6402
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• 2015

This research was performed to review operating parameters, optimum condition and check characteristic of microbubble generation for using bubble size distribution according to venturi specification. Optimum operating condition have airflow rate 0.3 LPM, 3 bar(pressure tank) and connecting nozzle directly(without valve), it is advantageous to generate microbubble. In case of characteristic of microbubble generation according to venturi specification, effect that nozzle specification affects bubble size distribution is low impact. But considering performance aspects, when using nozzle that throat diameter 3-4 mm, $D_{50}$ are $54.98-61.19{\mu}m$(D3L15, D4L15), fraction of bubble less than $50{\mu}m$ are 0.326, 0.345. And it is superior to others. Besides, $D_{50}$ and fraction of bubble less than $50{\mu}m$ of throat length 20 mm are $49.40-54.98{\mu}m$, 0.447, respectively And nozzle that throat length 20 mm is relatively tendency to generate microbubble stably.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.715-728
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• 2009

The Enterprise Service Bus based on Java Business Integration is an web service standard and one of the methods for implementing distribution channels of Service Oriented Architecture. Consisting of open source group, extensive venders and users, the ESB based JBI has the problems of ineffectiveness as well as advantages of extensibility of service plug-in. That is, in case users need to use Service plug-in, manual connection of packaging process and sequential distribution method is required. This study, therefore, proposes as a way of trouble-shooting the user-oriented component deployment tool which can manage entire process for deploying The ESB middleware platform to Service unit. At the same time, this study elicited the requirements based on issues of JBI-based ESB and has developed the modeling property, packaging, distribution and evaluation thru Schema analysis of JBI-compatible component. Using the deployment tool this study proposed, users will be able to perform and manage the whole deploying process without additional manual work for connecting component. Not only it is expected that interface based on Graphic User Interface provide usability and convenience but they can also minimize the errors rate through component and route validity verification function provided in deployment tool.

• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1049-1056
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• 2021

The purpose of this study was to develop a respiratory synchronization device for X-ray (X-RSD) to increase the reproducibility of inspiration when examining the Chest X-ray of a patient who difficulty in breathing coordination. The X-RSD was self-made using an air pressure sensor and air was injected by connecting a ventilator to the mannequin for CPR. At this time, the amount of injected air was quantified using the SkillReporting device. After placing the X-RSD on the chest of the mannequin, the amount of air was tested in 6 steps from 200 to 700 cc by 100 cc increased. For the accuracy evaluation, the sensitivity of X-RSD was measured by repeating a total of 80 measurements, and the sensitivity was 100%, and very precise results were obtained. After that, the images examined while viewing the X-RSD of the chest lateral examination and the images obtained by the blind examination were compared and evaluated. The lung volume of X-RSD was larger than that of the blind test, and the deviation was smaller. Overall, the use of X-RSD can help with chest X-ray examination of patients who have difficulty in cooperating, and it is thought that it will be possible to contribute to the reduction of exposure dose by reducing the repeat rate of general X-ray examinations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.412-424
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• 2019

In this study, the changes of the streamflow characteristics of the watershed were analysed depending on the infiltration methods of CAT. The study area, Boryeong-dam watershed located in Chungcheongnam-do area, has been suffered from severe drought in recent years and stabilized regarding on the storage rate through efforts such as constructing a channel connecting the upstream of Boryeong-dam from the downstream of the Geum river. In this study, the effects of soil infiltration parameters on the watershed streamflow characteristics were analyzed by the infiltration methods of CAT such as Rainfall Excess, Green&Ampt and Horton. And the parameter calibrations were conducted by SCEUA-P, a global optimization technique module of the PEST, the package for parameter optimization and uncertainty analysis, to compare the yearly variations of soil parameters for infiltration methods of CAT. In addition, the streamflow characteristics were analyzed for three infiltration methods by applying three different scenarios, such as applying calibrated parameters for every years to simulate the model for each years, applying calibrated parameters for the entire period to simulate the model for entire period, and applying the average value of yearly calibrated parameters to simulate the model for entire period.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.320-330
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• 2022

The Hangang river estuary, which is a natural estuary without structures such as estuary barrage, is an ecological pathway connecting the sea and rivers. Accordingly, Hangang river estuary has various species, and there is very valuable. Sediment classification in Hangang river estuary is three-dimensionally and diversely is distributed. Sediment classification in Hangang river estuary is also sensitively changed according to various factors such as climate change and river development. It is typically cause to landform and to develop a compound cross section. In Janghang wetland, the plant success is remarkable according to the morphological change at river bed. The purpose of this study is to identify the mechanism of wetland formation based on the observation on-site. As a result of the observation, Janghang wetland where was artificially created, has been grown according to the river bed change based on the flow rate and the plant success. The viscous surface layer material(fine grains of wash rod properties), which is not the main material(sand) of the river bed, but sub-materials of river bed, jas been settled on the pioneer plants(bolboschoenus planiculmis, etc.). It is an important role in the growth of a compound cross section and a wetland. After the wetland developed to the compound cross section, it is observed that the pioneer plants are transferred to other plant species.