• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.54-59
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• 2020

Coarse aggregate is produced in various ways depending on the location and production method. Currently, the construction industry is in need of a stable supply of coarse aggregate and a way to secure standard quality. The purpose of this study is to examine whether the use of coarse aggregate in 3D printing can help solve this problem. ABS filament was selected for use in 3D printing. CATIA was used for the design of the coarse aggregate, and CUBICON Single Plus was used for the production. Six specimens were produced and cured in water for 28 days. Three of them were made with AE agent, and three were made without it. A compressive strength test confirmed that when the AE agent was used, the compressive strength was greater than the lightweight concrete design criterion specified in the concrete standard specification. This suggests that coarse aggregate produced by a 3D printer may be used for lightweight concrete. A mass production system using this method could help to solve the problems facing the construction industry, such as stable supply and demand for coarse aggregate and securing standard quality.

• Journal of the Korean Society for information Management
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• v.33 no.2
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• pp.77-102
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• 2016

The effective searching for performing arts contents can be achieved by providing various access points and searching methods based on specialized metadata. The purpose of this study is to develop a faceted navigation interface which user could effectively and efficiently retrieve performing arts contents even if the users do not know accurate descriptive information about them. Therefore, the study, first, investigated search access points and navigation items providing by other the performing arts retrieval systems and to analyze information seeking behaviors of university students who major in music, dance and theater. And then, the study proposed the 36 facets with the 9 main facet categories suitable for performing arts and also proposed 27 descriptive elements suitable for performing arts contents. Finally, the study developed the performing arts contents retrieval system based faceted navigation interface with 3,360 experimental data and conducted an in-depth interview in terms of usability, serendipity, and efficiency. The applying the faceted navigations for searching performing arts contents will help users access and utilize them in the retrieval system and moreover satisfy user demands.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.9-16
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• 2016

Wireless sensor networks (WSN) are composed of sensor nodes and a base station. The sensor nodes deploy a non-accessible area, receive critical information, and transmit it to the base station. The information received is applied to real-time monitoring, distribution, medical service, etc.. Recently, the WSN was extended to mobile wireless sensor networks (MWSN). The MWSN has been applied to wild animal tracking, marine ecology, etc.. The important issues are mobility and energy consumption in MWSN. Because of the limited energy of the sensor nodes, the energy consumption for data transmission affects the lifetime of the network. Therefore, efficient data transmission from the sensor nodes to the base station is necessary for sensing data. This paper, proposes an energy consumption model using two-tier clustering in mobile sensor networks (TTCM). This method divides the entire network into two layers. The mobility problem was considered, whole energy consumption was decreased and clustering methods of recent researches were analyzed for the proposed energy consumption model. Through analysis and simulation, the proposed TTCM was found to be better than the previous clustering method in mobile sensor networks at point of the network energy efficiency.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.385-394
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• 2009

Face tracking and recognition are difficult problems because the face is a non-rigid object. The main reasons for the failure to track and recognize the faces are the changes of a face pose and environmental illumination. To solve these problems, we propose a nonlinear manifold framework for the face pose and the face illumination normalization processing. Specifically, to track and recognize a face on the video that has various pose variations, we approximate a face pose density to single Gaussian density by PCA(Principle Component Analysis) using images sampled from training video sequences and then construct the GMM(Gaussian Mixture Model) for each person. To solve the illumination problem for the face tracking and recognition, we decompose the face images into the reflectance and the illuminance using the SSR(Single Scale Retinex) model. To obtain the normalized reflectance, the reflectance is rescaled by histogram equalization on the defined range. We newly approximate the illuminance by the trained manifold since the illuminance has almost variations by illumination. By combining these two features into our manifold framework, we derived the efficient face tracking and recognition results on indoor and outdoor video. To improve the video based tracking results, we update the weights of each face pose density at each frame by the tracking result at the previous frame using EM algorithm. Our experimental results show that our method is more efficient than other methods.

• The KIPS Transactions:PartA
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• v.16A no.3
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• pp.169-180
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• 2009

With fixed sinks, the network stability could be improved while the network life time could be decreased by the rapid energy dissipation around the fixed sink because of the concentrated network traffic from sensor nodes to the fixed sink in wireless sensor network. To address this problem, mobile sinks, which decentralize the network traffic, has received a lot of attention from many researchers recently. Since a mobile sink has a limited period to communicate with each sensor nodes, it is necessary for a scheduling algorithm to provide the fairness of data collection from each sensor nodes. In the paper, we propose the new scheduling algorithm, ASF(Availability based Scheduling scheme for Fair data collection), for the fair data collection by a mobile in the sensor networks. The ASF takes account of the distance between each sensor nodes and the mobile sink as scheduling metric, as well as the amount of collected data from each sensor nodes. Experiment results shows that the ASF improves the fairness of data collection among the sensor nodes, comparing to existing algorithm.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.2
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• pp.162-169
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• 2018

The purpose of this study was to compare the validity of $Cariview^{(R)}$, a new colorimetric caries activity test, with $CRT^{(R)}$ bacteria, a conventional bacterial culture method. In addition, this study assesses the correlation between the dental caries experience and activity between mothers and their children. 34 pairs of mothers and their children under the age of 6 years participated in this study with informed consent. After filling out a questionnaire and oral examination, the two caries activity tests above were performed on each subject. In the results, $Cariview^{(R)}$ scores were statistically significant with children's caries experience (r = 0.598, p < 0.01) and showed higher correlation than $CRT^{(R)}$ bacteria scores. $Cariview^{(R)}$ scores showed statistically significant correlation with the number of decayed teeth in both mothers and children (p < 0.05). In both $Cariview^{(R)}$ and $CRT^{(R)}$ bacteria tests, there was no statistically significant correlation between caries experience and caries activity (p > 0.05). $Cariview^{(R)}$ colorimetric test will be clinically useful for predicting future caries risk and establishing a preventative strategy in pediatric dentistry.

• Journal of Navigation and Port Research
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• v.38 no.2
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• pp.155-162
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• 2014

In container terminals, stacking yard is the place where import and export containers are temporarily stored before being loaded onto or after being discharged from a ship. Since all the containers go through the stacking yard in their logistic flow, the productivity of the terminal critically depends on efficient operation of stacking yard, which again depends on how well the stacking locations of the incoming containers are determined. However, a good location for stacking an incoming container later can turn out to be a bad one when that container is to be fetched out of the stacking yard, especially if some rehandling is required. This means that good locations for the containers are changing over time. Therefore, in most container terminals, the so-called remarshaling is done to move the containers from bad location to good locations. Although there are many previous works on remarshaling, they all assume that the remarshaling can be done separately from the main jobs when the cranes are idle for rather a long period of time. However, in reality, cranes are hardly available for a period long enough for remarshaling. This paper proposes a crane dispatching strategy that allows remarshaling jobs to be mixed together with the main jobs whenever an opportunity is detected. Experimental results by simulation reveals that the proposed method effectively contributes to the improvement of terminal productivity.

• Applied Microscopy
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• v.37 no.4
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• pp.239-248
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• 2007

Alteration of temperature is one of cancer therapies. In general, severe hyperthermia(around $43^{\circ}C$) and hypothermia(around $18^{\circ}C$) trigger apoptosis through mitochondria, though the specific mechanism is still unknown. CC-t6 and GB-d1 cell lines, which were originally derived from human cholangiocarcinoma and gall bladder cancer, were established from a metastatic lymph node. To investigate the mechanism of metastatic cancer cell response to thermal stresses, hyperthermia($37^{\circ}C{\rightarrow}43^{\circ}C$) and hypothermia($37^{\circ}C{\rightarrow}17.4^{\circ}C$) were designed. Thermal stresses did not induce apoptosis but necrotic cell death. Any alterations of caspase-3, -9, cytochrome c, Bax, and Bcl-2 were not found in both hyperthermia and hypothermia exposed fells using western blot analysis. In the transmission electron microscopy, typical necrotic, but not apoptotic, changes were observed. These results suggest that temperature changes induce cell death through necrotic pathway in metastatic cancer in vitro, and it can be one of effective anticancer methods.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.14 no.2
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• pp.57-62
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• 1978

When fisherman use the boat seine net to catch anchovy, a large noise (drum can, small drum and small gong) is used to scare the anchovy school along the wing nets, and into the bag net were they are caught. We want to know how much of an effect these s:mnds have on forceing the anchovy school towards the bag net. The underwater sounds of ancho\'y, drum can, small drum and small gong were analyzed in the labroatory. The behavioral responeses to the playback sounds of anchovy feeding and sounds of artificial instruments were also investigated. The feeding and artificial sounds of the samples were recorded by a tape recorder through a hydrophone in an anechoic aquarium. The sound intensity level was measured by means of a sound level meter in an anechoic chamber. The frequency and intensity of various sounds were analyzed with an analyzing system consisting of a ~-octave filter set, a high speed level recorder, an amplifier and an oscilloscope. The most successful recording was edited into a 9 to 10 second sound track and was repeated in a sequence of 9 to 10 second intervals. The sequence was then reproduced into an anechoic aquarium through the underwater speaker. The results of investigation are as follows; 1. The frequency of the feeding sound was 63~80Hz, and the pressure level produced was less than 32db. 2. The frequencies of the artificial sounds were 315~ 1,OOOHz, and the pressure levels were 88~95 db in the air. 3. When a hydrophone was placed 70cm below the surface with artificial sounds (drum can, small drum and small gong) produced 1 meter above the surface, the pressure level decreased about 30db. 4. The feeding sound was ineffective in attracting the anchovy, because of interference from ambient noise. 5. The artificial sounds had such a small effect on the anchovy's that they could not be used in ocean fisheries.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.93-99
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• 1999

The alkaline single-cell gel electrophoresis (SCGE) assay, called the comet assay, has been applied to the detection of DNA damage from a number of chemical and biological factors in vivo and in vitro. The comet assay is a novel method to assess DNA single-strand breaks, alkali-labile sites in individual cells. The effect of peach kernel extracts on radiation-induced DNA damage in human blood lymphocytes was evaluated by the SCGE assay. The lymphocytes, with or without pretreatment of the extracts, were exposed to 0, 0.1, 0.3, 0.5, 1.0 and 2.0 Gy of $^{60}Co$ gamma ray. Significantly increased tail moment, which was a marker of DNA strand breaks in the comet assay, showed an excellent dose-response relationship. The treatment of the peach kernel extracts reduced the DNA damage by 30 % in irradiated groups as compared to that in non-treated control groups. The result indicates that the extracts shows radioprotective effect on lymphocyte DNA when assessed by the comet assay.