• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.808-820
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• 2006

In regard to indoor air quality patterns, the government introduced various polices that were about managing and monitoring quality of indoor air as a major assignment, and also executed 'Indoor Air Quality Management Act' which was presented in the May, 2004. However, among the multi-usage facilities controlled by the Act, the school was not included yet. This study goal was to investigate PM 10 pollution patterns of the high school classrooms using a pattern recognition method based on cluster analysis and disjoint principal component analysis, and further to survey levels of inorganic elements in May, June, and September, 2004. A hierarchical clustering method was examined to obtain possible objects in pseudo homogeneous sample classes by transformation raw data and by applying various distance. Following the analysis, the disjoint principal component analysis was used to define homogeneous sample class after deleting outliers. Then three homogeneous Patterns were obtained as follows: the first class had been separated and objects in the class were considered to be sampled under semi-open condition. This class had high concentration of Ca, Fe, Mg, K, Al, and Na which are related with a soil and a chalk compounds. The second class was obtained in which objects were sampled while working air-conditioners and was identified low concentration of PM 10 and elements. Objects in the last class were assigned during rainy day. A chalk, soil element and various types of anthropogenic sources including combustions and industrial influenced the third class. This methodology was thought to be helpful enough to classify indoor air quality patterns and indoor environmental categories when controlling an indoor air quality.

• Journal of Biosystems Engineering
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• v.42 no.2
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• pp.75-79
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• 2017

The use of tractors to carry out agricultural work has played an important role in mechanizing the agricultural sector. A repairable mechanical system (such as an agricultural tractor) is subject to deterioration or failure. In this study, a regression model was used to predict the failure rate of a John Deere 3140 tractor. The machine failure pattern was carefully studied, and key factors affecting the failure rate were identified in five regions of the Khouzestan province. Through a questionnaire, data was obtained from farm records. This data was grouped into six sub-groups, according to the annual use hours (AUH) and the manner in which the tractors were stored. Results showed that AUH and storage policies affected failure rate slightly. With an increase in the age of the tractors, the failure rate in the tractors used for 1050-2000 hours annually and stored outdoors was higher than those used for 200-1000 hours annually and stored in sheds. When the tractors were of the same age, the slope of the curve in the 200-1000 annual use hours increased gradually and then rapidly, but failure rate in the 1050-2000 annual use hours was high from the beginning, and subsequent increase in this value was almost uniform. As a result, it can be said that with an increase in the annual use hours, the failure and breakdown rate in John Deere 3140 tractors rapidly increases, but maintenance conditions only slightly affect the failure and breakdown rate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.6
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• pp.1881-1900
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• 2014

Since 802.11 wireless LANs are so widely used, it has become common for numerous access points (APs) to overlap in a region, where most of those APs are managed individually without any coordinated control. This pattern of wireless LAN usage is called the private OBSS (Overlapping Basic Service Set) environment in this paper. Due to frame collisions across BSSs, each BSS in the private OBSS environment suffers severe performance degradation. This study approaches the problem from the perspective of congestion control rather than noise or collision resolution. The retry limit, one of the 802.11 attributes, could be used for traffic control in conjunction with TCP. Reducing the retry limit causes early discard of a frame, and it has a similar effect of random early drops at a router, well known in the research area of congestion control. It makes the shared link less crowded with frames, and then the benefit of fewer collisions surpasses the penalty of less strict error recovery. As a result, the network-wide performance improves and so does the performance of each BSS eventually. Reducing the retry limit also has positive effects of merging TCP ACKs and reducing HOL-like blocking time at the AP. Extensive experiments have validated the idea that in the OBSS environment, reducing the retry limit provides better performance, which is contrary to the common wisdom. Since our strategy is basically to sacrifice error recovery for congestion control, it could yield side-effects in an environment where the cost of error recovery is high. Therefore, to be useful in general network and traffic environments, adaptability is required. To prove the feasibility of the adaptive scheme, a simple method to dynamically adjust the value of the retry limit has been proposed. Experiments have shown that this approach could provide comparable performance in unfriendly environments.

• Journal of the Korean Society of Food Culture
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• v.19 no.4
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• pp.447-459
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• 2004

Fortified foods are consumed widely in modem society according to increased concern on health oriented foods. This study investigated the patterns of vitamin-and/or mineral-fortified food use among 677 teenage students(13-18 years of age) in Chungnam province and Daejeon city in Korea using questionnaire. More than 63.7% of total subjects consumed more than one package of fortified foods belonged to more than three categories of five categories including sweets/biscuits, ramyons, beverages, milk and dairy products, and breads as a frequency of more than 1-2 times/week during previous three months prior to present survey. Consumption of fortified foods was higher in middle school students than in high school students(p<0.05), and in females than in females(p<0.001). Users of fortified foods took the snacks more often(p<0.001), and they tended to believe more positively that fortification can be helpful in health maintenance than did non-users. Users preferred vitamin C and Ca(calcium) as a fortified nutrient. Major fortified nutrients in fortified foods taken by users were various; vitamin B-complex and Ca from sweets/biscuits, Ca from ramyons, vitamin C and Ca from beverages, Ca and iron from milk and dairy products and breads. These results suggest that fortified foods are used commonly and are influenced by several factors among teenagers. Types of fortified nutrient, in fortified foods taken by subjects, are various and fortification is performed unspecifically. As a consequence both nutrition education and government regulation on fortified foods should be enforced to maximize the benefits and minimize the hazard of their use.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.2
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• pp.81-85
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• 2007

Glucocorticoid hormone regulates numerous physiological processes, such as regulation of metabolism, and anti-inflammatory and immunosuppressive actions via the activation and repression of gene expression. Here we described a lentivirus-based reporter vector system expressing red fluorescent protein (mRFP) or firefly luciferase (Luc) under the control of a glucocorticoid-responsive element that allows observation of the temporospatial pattern of glucocorticoid induced GR-mediated signaling on a cellular level. Moreover, usage of the chromatin insulator of the chicken ${\beta}$-globin locus induced a marked increase of sensitivity of glucocorticoid inducible promoter of a reporter gene. Use of this method will be applicable of screening for agonist and antagonist of GR in vitro, and also a reporter gene assay for the in vivo determination of the GR-mediated gene activation.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.2
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• pp.111-118
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• 2015

Objectives Through the clinical records of Seungjeongwon Ilgi, we reviewed the usage of Bi-Jeung to know the concept of the word and studied therapeutic strategies for managing Bi-Jeung. Methods We investigated the clinical records of the mid-Chosun dynasty containing the key word "Bi" from electronic database (Seungjeongwon Ilgi). Results Of 4,039 records, 249 articles thought to have medicinal value were lastly selected. We subdivided the cases into 13 categories according to time, the connection of contents and the change of associated symptoms. "Bi" was not used alone but used in combination with body parts or other symptoms. Etiological causes of "Bi" involved dampness, phlegm, fire, heat and qi disorders. We suggested that "Bi" of the mid-Chosun dynasty meant a symptom group mainly of sensory impairment and additionally pain or motor disturbance. Among the 22 herbal medicine formulas used, 15 were based on internal medical pattern identifications and 7 were symptomatic treatments. Acupuncture and moxibustion therapy were primarily applied to adjacent acupoints. In addition, External therapies were used together, such as washing therapy, plaster therapy, cupping therapy and thermotherapy. Conclusions "Bi" principally indicated sensory impairment on limbs and the main etiological cause was considered to be dampness. Herbal medicine, acupuncture, moxibustion and external therapies were used to cure Bi-Jeung.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.1
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• pp.84-93
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• 2018

In this paper, we propose an Elman recurrent neural network to predict and analyze a time series of power energy consumption. To this end, we consider the volatility of the time series and apply the sample variance and the detrended fluctuation analyses to the volatilities. We demonstrate that there exists a correlation in the time series of the volatilities, which suggests that the power consumption time series contain a non-negligible amount of the non-linear correlation. Based on this finding, we adopt the Elman recurrent neural network as the model for the prediction of the power consumption. As the simplest form of the recurrent network, the Elman network is designed to learn sequential or time-varying pattern and could predict learned series of values. The Elman network has a layer of "context units" in addition to a standard feedforward network. By adjusting two parameters in the model and performing the cross validation, we demonstrated that the proposed model predicts the power consumption with the relative errors and the average errors in the range of 2%~5% and 3kWh~8kWh, respectively. To further confirm the experimental results, we performed two types of the cross validations designed for the time series data. We also support the validity of the model by analyzing the multi-step forecasting. We found that the prediction errors tend to be saturated although they increase as the prediction time step increases. The results of this study can be used to the energy management system in terms of the effective control of the cross usage of the electric and the gas energies.

• The Research Journal of the Costume Culture
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• v.17 no.2
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• pp.255-269
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• 2009

The purpose of this study was to understand the internet fashion shopping behavior of men in their 20s, and to develop the internet shopping website with situation-based clothing coordination services for male comsumer in their 20s. The study was implemented through a normative descriptive survey method using a questionnaire. The survey was conducted in April and May 2006, and the sample group consisted of 280 men in their 20s from Busan and the provinces of Gyeongnam and Gyeongbuk. The data was analyzed by following statistical methods: frequency analysis, one-way-ANOV A, and Scheffe's test. The results are as follow: first, regarding internet the usage trend of male consumers in their 20s, it was shown that they usually spent more than 15 minutes and less than 30 minutes for internet shopping the price range from their experiences of clothing purchases was relatively high for they bought jackets or suits was relatively high. Second, an analysis on men's pattern of clothing purchase showed that many respondents purchase single items such as shirts or pants online. Third, in terms of their experiences of online purchase of coordinated clothes, 69% said "none." Yet, they showed positive assessment to a question whether they are willing to purchase clothes by using a situation-based coordination service or a 1:1 online coordination services. Fourth, the relationship between consumers' reactions to online situation-based clothing coordination services and respondents' demographic characteristics showed statistically significant different results in terms of occupation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.324-327
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• 2013

Recently, due to evolving cloud computing technology, we can easily and transparently utilize both local computing resource and remote computing resource in real life. Especially, enhancing smart device technologies and network infrastructures promote an increase of needs to share files between local smart devices and cloud storages. However, since smart devices have a limited storage space, storing files on cloud storage causes a starvation problem of local storage. It means that users can face a storage-lack problem even a cloud storage service provide a huge file storing space. In this research, we propose a method to manage files between smart devices and cloud storages. Our approach calculate file usage pattern based on recently used date, and then this approach determines local files being migrated. As a result, our approach is sufficient for handling data synchronization between big data storage farm and local thin client which contains limited storage space.

• Journal of Pharmaceutical Investigation
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• v.40 no.6
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• pp.353-356
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• 2010

Although liposomes have been applied as drug delivery systems in various fields, the usage was limited due to the low encapsulation efficiency compared to other carrier systems. Here, cationic liposomes were prepared by mixing 1,2-dioleoyl-3-trimethylammoniopropane (DOTAP) as a cationic lipid, 1,2-dioleoyl-sn-glycerol-phosphoethanolamine (DOPE) and cholesterol (CH), and the liposomes were hydrated by varying the aqueous phases such as phosphate-buffered saline (PBS), 5% dextrose, and 10% sucrose in order to improve the encapsulation efficiency of bovine serum albumin (BSA). The particle size and zeta potential were determined by dynamic light scattering method and in vitro release patterns were investigated by spectrophotometry. Particle size and zeta potential of liposomes were varied depending on the ratio of DOTAP/DOPE/CH in range of 270-350 nm and 0.8-9.7 mV, respectively. Moreover, the addition of polyethylene glycol (PEG) improved the encapsulation efficiency from 37% to 43% as well as reduced particle sizes of liposomes while the liposomes were hydrated in PBS. When the liposomes were hydrated with 10% sucrose, the encapsulation efficiency of BSA was higher than any other groups. Whereas PBS was used as hydration solution, lower encapsulation efficiency was obtained compared with other groups. More than 60% of BSA was released from the liposomes hydrated with 10% sucrose; thereafter another 20% of BSA was released. Therefore, release pattern of BSA from cationic liposomes was extended release in this study. From the results, cationic liposomes dispersed in 10% sucrose would be potential carrier with high encapsulation efficiency.