• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.540-543
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• 2007

최근의 그리드 컴퓨팅 시스템 환경은 단일 환경에서 작게는 2~4CPU, 많게는 수백 CPU 이상의 시스템으로 구축되고 있고, 더욱이 지역적으로도 멀리 떨어져 있다. 따라서 이를 운용하는 기업에서는 시스템의 사용 현황을 신속하게 분석할 필요가 있다. 그러나 이렇게 혼재된 이 기종 및 컴퓨팅 환경하에서의 각 지역별 시스템 사용현황을 효과적으로 분석 한다는 것은 매우 어려운 일이다. 기존에 사용되어 온 그리드 컴퓨팅 시스템 환경에서의 사용율 관리 방법들은 Queueing 시스템이 가지고 있는 Accounting 분석 명령어로 text 형태의 Accounting raw data 의 결과를 추출하여 가공 처리하므로 데이터 증가 시 반응 속도가 현격하게 느려지는 상황이 발생한다. 또한 원격지 그리드 컴퓨팅 시스템 군의 사용율 분석은 데이터 분석 시 매번 원격지접근 절차를 사용하여 그리드 컴퓨팅 시스템 군에 접근한 후 해당 로컬 시스템 분석을 해야 하고 각 원격지시스템군별로 추출 된 데이터를 통합 관리해야 하는 문제점을 가지고 있다. 따라서 이러한 문제점을 해결하고자 하는 것이 본 논문에서 제안하는 3-tier 구조의 GSA(Grid System Account)이다. 제안한 GSA 는 각 원격지 별 데이터를 객체화하여 Database 에 저장 함으로써 데이터 분석 시 효과적으로 처리할 수 있으며, 다수의 원격지 그리드 컴퓨팅 시스템 군에 대한 복합적인 분석이 필요할 때 효율적으로 대처할 수 있다. 본 논문에서는 GSA 의 설계방법을 제안하고 구현하여 실 성능을 시험함으로써 보다 효율적인 그리드 컴퓨팅 시스템의 사용율 분석 관리가 가능함을 보였다.포는 감수성을 보이지 않았다. 따라서 위의 결과로부터 SLT-I에 감수성을 보이지 않은 Raw264.7세포를 대상으로 Gb3 발현 정도와 SLT-I의 세포독성의 관계를 규명하고자 Gb3의 발현을 증가시킨 후 SLT-I의 세포독성을 재차 평가하였다. 이 결과 $TNF-{\alpha}$의 처리에 의하여 6 hrs에 Gb3의 발현이 정점(43.5%)에 이르렀으며 36 hrs에 정상 수준(25.0%)으로 환원되었다. 그러나, Gb3의 발현이 증가함에도 불구하고 SLT-I의 세포독성에는 변화가 관찰되지 않았다. 따라서, SLT-I에 의한 세포독성은 세포의 종류에 따라서 다르며 또한, Gb3의 발현정도에만 의존적이지는 않을 것으로 생각된다. 이와 같은 결과는 E. coli 0157의 감염증 병인 연구에 있어 SLT-I과 Gb3의 발현의 상관관계에 대한 보다 심도 있는 연구가 필요함을 시사한다.만 분할률, 배반포 형성률 및 배반포의 세포수를 증가시키는 것으로 사료된다.수의 유출입 지점에 온도센서를 부착하여 냉각수의 온도를 측정하고 냉각수의 공급량과 대기의 온도 등을 측정하여 대사열의 발생을 추정할 수 있었다. 동시에 이를 이용하여 유가배양시 기질을 공급하는 공정변수로 사용하였다 [8]. 생물학적인 폐수처리장치인 활성 슬러지법에서 미생물의 활성을 측정하는 방법은 아직 그다지 개발되어있지 않다. 본 연구에서는 슬러지의 주 구성원이 미생물인 점에 착안하여 침전시 슬러지층과 상등액의 온도차를 측정하여 대사열량의 발생량을 측정하고 슬러지의 활성을 측정할 수 있는 방법을 개발하였다.enin과 Rhaponticin의 작용(作用)에 의(依)한 것이며, 이

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.192-203
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• 2009

In the new Seoul-Busan high speed railroad construction specially in area of city center passage the roadbed establishment is recommended the staibility for the existing subway tunnel segments of Busan subway 1st and 2nd lines regarding the appearance condition, a quality condition and the durability of the objective facility, and it evaluates the numerical analysis using MIDAS/GTS which leads the stability of the objective facility and investigatesd tunnels. Fundamental issues in tunneling under high groundwater table are discussed and the effect of groundwater on tunnel excavation was examined using a 3D stress-pore pressure coupled Finite-Element Method. Based on the results the interaction mechanism between the tunnelling and groundwater is identified. In the both of 1st and 2nd Line the maximum sinkage, unequal sinkage and the lining stress from numerical analysis are within permission and the damage degree is appearing to be disregarded. But it enforces necessary Pre-grouting in order to minimize an actual tunnel face conduct and when the tunnel is excavated it is also necessary to minimize the outflow possibility.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.4
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• pp.236-244
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• 2024

A representative problem in domestic chestnut industry is the high loss of flesh due to excessive knife peeling in order to increase the peeling rate, resulting in a decrease in production efficiency. In this study, a prediction model for weight loss rate of chestnut by stage of knife peeling process was developed as undergarment study to optimize conditions of the machine. 51 control conditions of the two-stage blade peeler used in the experiment were derived and repeated three times to obtain a total of 153 data. Machine learning(ML) models including artificial neural network (ANN) and random forest (RF) were implemented to predict the weight loss rate by chestnut peel stage (after 1st peeling, 2nd peeling, and after final discharge). The performance of the models were evaluated by calculating the values of coefficient of determination (R), normalized root mean square error (nRMSE), and mean absolute error (MAE). After all peeling stages, RF model have better prediction accuracy with higher R values and low prediction error with lower nRMSE and MAE values, compared to ANN model. The final selected RF prediction model showed excellent performance with insignificant error between the experimental and predicted values. As a result, the proposed model can be useful to set optimum condition of knife peeling for the purpose of minimizing the weight loss of domestic chestnut flesh with maximizing peeling rate.

• The Korean Journal of Applied Statistics
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• v.37 no.4
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• pp.525-539
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• 2024

Massive multiplayer online role playing game (MMORPG) is a common type of game these days. Predicting user churn in MMORPG is a crucial task. The retention rate of users is deeply associated with the lifespan and revenue of the service. If the churn of a specific user can be predicted in advance, targeted promotions can be used to encourage their stay. Therefore, not only the accuracy of churn prediction but also the speed at which signs of churn can be detected is important. In this paper, we propose methods to identify early signs of churn by utilizing the daily predicted user retention probabilities. We train various deep learning and machine learning models using log data and estimate user retention probabilities. By analyzing the change patterns in these probabilities, we provide empirical rules for early identification of users at high risk of churn. Performance evaluations confirm that our methodology is more effective at detecting high risk users than existing methods based on login days. Finally, we suggest novel methods for customized marketing strategies. For this purpose, we provide guidelines of the percentage of accessed users who are at risk of churn.

• Information Systems Review
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• v.26 no.2
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• pp.137-153
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• 2024

This study aimed to propose early diagnosis and management of dementia, which is increasing in aging societies, and suggest commercial utilization strategies by leveraging digital healthcare technologies, particularly lifelog data collected from wearable devices. By introducing new approaches to dementia prevention and management, this study sought to contribute to the field of dementia prediction and prevention. The research utilized 12,184 pieces of lifelog information (sleep and activity data) and dementia diagnosis data collected from 174 individuals aged between 60 and 80, based on medical pathological diagnoses. During the research process, a multidimensional dataset including sleep and activity data was standardized, and various machine learning algorithms were analyzed, with the random forest model showing the highest ROC-AUC score, indicating superior performance. Furthermore, an ablation test was conducted to evaluate the impact of excluding variables related to sleep and activity on the model's predictive power, confirming that regular sleep and activity have a significant influence on dementia prevention. Lastly, by exploring the potential for commercial utilization strategies of the developed model, the study proposed new directions for the commercial spread of dementia prevention systems.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.688-693
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• 2014

For investigating NO reduction activity of an catalytic filter, the catalytic performance was measured under the presence of $SO_2$ and $H_2O$, respectively or simultaneously in the simulation gas composed of NO, $NH_3$, and air. The catalytic filter was prepared by coating $V_2O_5-WO_3/TiO_2$ catalyst on the pore surface of SiC filter element of which the superior performance for the particulate removal was well known. At the temperature below $260^{\circ}C$, the catalytic activities were enormously decreased under the presence of $SO_2$ and $H_2O$, respectively or simultaneously, compared with those under the cases of the absence of $SO_2$ and $H_2O$. However, the presence of $SO_2$ promoted the performance of the catalytic filter above $320^{\circ}C$ with showing the NO conversion better than 99.8% for the NO inlet concentration of 500 ppm and at the face velocity of 2 cm/s. In particular, the presence of water showed high NO conversion higher than 99% up to high temperature of $380^{\circ}C$. This effect of water was explained by the reason that it retarded the ammonia oxidation which is the main step into the formation of $N_2O$. The initial NO reduction activity of the catalytic filter maintained for the duration of 100 hours in the presence of $SO_2$ and $H_2O$. Therefore, it was concluded that the catalytic filter was promisingly useful for the industrial NOx reduction catalyst in order to treat the particulate and NO simultaneously.

• Journal of KIISE:Databases
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• v.32 no.4
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• pp.452-472
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• 2005

We propose XIR-Branching, a novel method for processing partial match queries on heterogeneous XML documents using information retrieval(IR) techniques and novel instance join techniques. A partial match query is defined as the one having the descendent-or-self axis '//' in its path expression. In its general form, a partial match query has branch predicates forming branching paths. The objective of XIR-Branching is to efficiently support this type of queries for large-scale documents of heterogeneous schemas. XIR-Branching has its basis on the conventional schema-level methods using relational tables(e.g., XRel, XParent, XIR-Linear[21]) and significantly improves their efficiency and scalability using two techniques: an inverted index technique and a novel prefix match join. The former supports linear path expressions as the method used in XIR-Linear[21]. The latter supports branching path expressions, and allows for finding the result nodes more efficiently than containment joins used in the conventional methods. XIR-Linear shows the efficiency for linear path expressions, but does not handle branching path expressions. However, we have to handle branching path expressions for querying more in detail and general. The paper presents a novel method for handling branching path expressions. XIR-Branching reduces a candidate set for a query as a schema-level method and then, efficiently finds a final result set by using a novel prefix match join as an instance-level method. We compare the efficiency and scalability of XIR-Branching with those of XRel and XParent using XML documents crawled from the Internet. The results show that XIR-Branching is more efficient than both XRel and XParent by several orders of magnitude for linear path expressions, and by several factors for branching path expressions.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.204-208
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• 2012

Water repellency which affects infiltration, evaporation, erosion and other water transfer mechanisms through soil has been observed under several natural conditions. Water repellency is thought to be caused by hydrophobic organic compounds, which are present as coatings on soil particles or as an interstitial matter between soil particles. This study was conducted to evaluate the characteristics of the water repellent soil and transport characteristics of trace elements within this soil. Capillary height of the water repellent soil was measured. Batch and column studies were accompanied to identify sorption and transport mechanism of trace elements such as $Cu^{2+}$, $Mn^{2+}$, $Fe^{2+}$, $Zn^{2+}$ and $Mo^{5+}$. Difference of sorption capacity between common and repellent soils was observed depended on the degree of repellency. In the column study, the desorption of trace elements and the spatial concentration distribution as a function of time were evaluated. The capillary height was in the repellency order of 0% > 15% > 40% > 70% > 100%. No water was absorbed in soil indicating >70% repellency. Using trace elements, $Fe^{2+}$ and $Mo^{5+}$ showed higher sorption capacity in the repellent soil than in non-repellent soil. The sorption performance of $Fe^{2+}$ was found to be in the repellency order of 40% > 15% > 0%. Our results found that transfer of $Mo^{5+}$ had similar sorption tendency in soils having 0%, 15% and 40% repellency at the beginning, however, the higher desorption capacity was observed as time passes in the repellent soil compared to in non-repellent soils.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.656-663
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• 2012

After the construction of waterworks automatic meter reading with 15 mm diameter digital water mater with magnetoresistance sensor developed in this study at 96 households of apartment complexes located in Incheon-City B-Gu S-Dong, the feasibility of field application of waterworks automatic meter reading was evaluated. The field application of waterworks automatic meter reading was performed from July to December in 2011, and average reception rate was as low as 84.6% due to the instable wibro networks, the existence of communication blackout and temporary malfunction of router. After the extraction of 10 households with one to five residents out of 96 households by using stratified random sampling method and analysis of domestic water use, it was found that domestic water use was significant at August and showed a decreasing trend at September, followed by increase in domestic water use at November and decrease in domestic water use at December. This phenomenon should be attributed to weather factors (temperature, humidity, etc.), which significantly affected domestic water use. Similar trend in domestic water use in terms of weather factors was obtained in case of Liter per capita day of water use after the extraction of 30 households out of 96 households by using stratified random sampling method. After analysis of Liter per capita day for 96 households, single residents increases resulted in reduction of domestic water usage by about 14% of Liter per capita day. These results might be due to the fact that domestic water usage such as laundry, beverages, catering, cleaning, etc. should be required for even the household with one resident, whereas domestic water usage for those common utilization can be significantly saved for the household with more than one resident.

• Journal of Korean Society of Steel Construction
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• v.27 no.6
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• pp.513-523
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• 2015

In steel moment frames constructed of H-shapes, strong-axis moment connections should be used for maximum structural efficiency if possible. And most of cyclic seismic testing, domestic and international, has been conducted for strong-axis moment connections and cyclic test data for weak-axis connections is quite limited. However, when perpendicular moment frames meet, weak-axis moment connections are also needed at the intersecting locations. Especially, both strong- and weak-axis moment connections have been frequently used in domestic practice. In this study, cyclic seismic performance of RBS (reduced beam section) weak-axis welded moment connections was experimentally investigated. Test specimens, designed according to the procedure proposed by Gilton and Uang (2002), performed well and developed an excellent plastic rotation capacity of 0.03 rad or higher, although a simplified sizing procedure for attaching the beam web to the shear plate in the form of C-shaped fillet weld was used. The test results of this study showed that the sharp corner of C-shaped fillet weld tends to be the origin of crack propagation due to stress concentration there and needs to be trimmed for the better weld shape. Different from strong-axis moment connections, due to the presence of weld access hole, a kind of CJP butt joint is formed between the beam flange and the horizontal continuity plate in weak-axis moment connections. When weld access hole is large, this butt joint can experience cyclic local buckling and subsequent low cycle fatigue fracture as observed in this testing program. Thus the size of web access hole at the butt joint should be minimized if possible. The recommended seismic detailing such as stickout, trimming, and thicker continuity plate for construction tolerance should be followed for design and fabrication of weak-axis welded moment connections.