• Journal of The Korean Society of Agricultural Engineers
• /
• v.60 no.6
• /
• pp.43-54
• /
• 2018

The accurate estimation of reference crop evapotranspiration ($ET_o$) is essential in irrigation water management to assess the time-dependent status of crop water use and irrigation scheduling. The importance of $ET_o$ has resulted in many direct and indirect methods to approximate its value and include pan evaporation, meteorological-based estimations, lysimetry, soil moisture depletion, and soil water balance equations. Artificial neural networks (ANNs) have been intensively implemented for process-based hydrologic modeling due to their superior performance using nonlinear modeling, pattern recognition, and classification. This study adapted two well-known ANN algorithms, Backpropagation neural network (BPNN) and Generalized regression neural network (GRNN), to evaluate their capability to accurately predict $ET_o$ using daily meteorological data. All data were obtained from two automated weather stations (Chupungryeong and Jangsu) located in the Yeongdong-gun (2002-2017) and Jangsu-gun (1988-2017), respectively. Daily $ET_o$ was calculated using the Penman-Monteith equation as the benchmark method. These calculated values of $ET_o$ and corresponding meteorological data were separated into training, validation and test datasets. The performance of each ANN algorithm was evaluated against $ET_o$ calculated from the benchmark method and multiple linear regression (MLR) model. The overall results showed that the BPNN algorithm performed best followed by the MLR and GRNN in a statistical sense and this could contribute to provide valuable information to farmers, water managers and policy makers for effective agricultural water governance.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.3
• /
• pp.493-500
• /
• 2017

Based on the data accumulated through EMU fault management, this paper examines the reliability of old railway car parts and proposes measurements to improve safety. Subway Line 7 of the Seoul Metropolitan Rapid Transit Corporation, auxiliary power unit (Static Inverter) of the EMU second version is a core equipment to supply power to various room-service units in cars and make an effect directly on passenger satisfaction. To analyze the pattern of failure throughout the field data over a long period of time, this analysis of statistics and reliability considers the operating environment and stress factors. This statistical analysis presents the correlation between failure and the temperature stress factors related to frequent failure occurring intensively in summer. In addition, throughout the analysis of the life of the IGBT inverter, the effect of the temperature stress factor was observed before and after the repair. As a result of an analysis of the optimal operating conditions considering two variations of EMU, such as variable load and outside temperature, a difference in the cooling capacity between the optimal operating conditions and frequent failure conditions was observed. Based on this analysis, this paper suggests a way to minimize cooling capacity difference for the optimal operational conditions.

• Journal of KIISE:Computer Systems and Theory
• /
• v.37 no.3
• /
• pp.172-183
• /
• 2010

Virtual memory systems (VM) reduce disk I/Os caused by page faults using page prefetching, which reads pages together with a desired page at a page fault in a single disk I/O. Operating systems including 4.4BSD attempt to prefetch as many pages as possible at a page fault regardless of page access patterns of applications. However, such an approach increases a disk access time taken to service a page fault when a high portion of the prefetched pages is not referenced. More seriously, the approach can cause the memory pollution, a problem that prefetched pages not to be accessed evict another pages that will be referenced soon. To solve these problems, we propose an adaptive page prefetching control scheme (APC), which periodically monitors access patterns of prefetched pages in a process unit. Such a pattern is represented as the ratio of referenced pages among prefetched ones before they are evicted from memory. Then APC uses the ratio to adjust the number of pages that 4.4BSD VM intends to prefetch at a page fault. Thus APC allows 4.4BSD VM to prefetch a proper number of pages to have a better effect on reducing disk I/Os, though page access patterns of an application vary in runtime. The experiment of our technique implemented in FreeBSD 6.2 shows that APC improves the execution times of SOR, SMM, and FFT benchmarks over 4.4BSD VM by up to 57%.

• Journal of Oriental Neuropsychiatry
• /
• v.20 no.2
• /
• pp.163-176
• /
• 2009

Objectives : To address most probable and suitable method for designing clinical trial intervening Traditional Korean Herbal Medicine on hwa-byung. Study Design : A systematic review of research studies of complementary and/or alternative medical(CAM) treatment of depression, and of domestic clinical trials of Traditional Korean Medicine, and of Chinese clinical trials of Traditional Chinese Medicine. Methods : Randomized, controlled trials(RCTs) of treatment of depression intervening herbal medicine were searched through MEDLINE, Cochrane Library, and CNKI databases. Also, domestic RCTs intervening Traditional Korean Herbal Medicine were searched through Korean Traditional Knowledge Portal and Korean studies Information Service System(KISS). Studies were evaluated using Iadad scale and self-designed tool for this study. Results : Thirty four RCT studies( 10 from MEDLINE, 16 from CNKI, 8 domestic studies) of herbal medicine met inclusion criteria. Mean Jadad score of studies published in English was 2.8${\pm}$0.79, in Chinese 1.94${\pm}$0.77, and in Korean 2.75${\pm}$0.71. Twenty one percent of studies included pattern differentiation in their inclusion criteria. Twenty nine percent of studies used combined treatment of herbal and conventional medicine. Among studies on depression, 9% included Complementary Medical assessing tools. Conclusions : There is shortage of domestic clinical trial involving herbal medicine. In China, studies tend to focus on investigating effect of Combined treatment of herbal and conventional medicine on depression. Clinical trial(s) of hwa-byung should provide good internal validity by describing methodology for randomization, double-blinding, and attrition. Also, specific guideline for clinical trial, including Traditional Korean Medical aspects across inclusion criteria, and assessing tools is needed.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.3
• /
• pp.261-269
• /
• 1989

Agricultural activities in Chejudo require more specialized weather services in this region. The meteorological information available from the Korea Meteorological Service (KMS) is limited in its areal coverage because the KMS stations are located along the narrow band of coastal area. topoclimatological technique which makes use of empirical relationships between the topography and the weather can be applied to produce reasonable estimates of the climatic variables such as air temperature and precipitation over remote land area where routine observations are rare. Presentation of these estimates in a from of fine-mesh grid map can also be helpful to upgrade the quality of weather services in this region. Altitude values of the 250 m grid points were read from a 1: 25000 topographic map and the mean altitude, the mean slope, and the aspect of the slope were determined for each 1 km$^2$ land area from these altitude data. Daily minimum air temperature data were collected from 18 points in Chejudo during the winter period from November 1987 to February 1988. The data were grouped into 3 sets based on synoptic pressure pattern. Departures from the KMS observations were regressed to the topographical variables to delineate empirical relationships between the local minimum temperature under specific pressure patterns and the site topography. The selected regression equations were used to calculate the daily minimum temperature for each 1 km$^2$ land area under the specific pressure patterns. The outputs were presented in a fine-mesh grid map with a 6-level contour capability.

• Journal of Digital Convergence
• /
• v.10 no.11
• /
• pp.427-432
• /
• 2012

The article herein suggested a compound repository and a descriptive method to develop a compound knowledge process. A data target saved in a compound knowledge repository suggested in this article includes all compound knowledge meta data and digital resources, which can be divided into the three following factors according to the purpose: user roles, functional elements, and service ranges. The three factors are basic components to describe abstract models of repository. In this article, meta data of compound knowledge are defined by being classified into the two factors. A component stands for the property about a main agent, activity unit or resource that use and create knowledge, and a context presents the context in which knowledge object are included. An agent of the compound knowledge process performs classification, registration, and pattern information management of composite knowledge, and serves as data flow and processing between compound knowledge repository and user. The agent of the compound knowledge process consists of the following functions: warning to inform data search and extraction, data collection and output for data exchange in an distributed environment, storage and registration for data, request and transmission to call for physical material wanted after search of meta data. In this article, the construction of a compound knowledge repository for recommendation system to be developed can serve a role to enhance learning productivity through real-time visualization of timely knowledge by presenting well-put various contents to users in the field of industry to occur work and learning at the same time.

• Korean Journal of Community Nutrition
• /
• v.7 no.2
• /
• pp.177-187
• /
• 2002

This study was done to determine the factors associated with childhood overweight in 721 sixth grade elementary school students, in Busan. The students' heights, weights, waist circumferences and triceps-skinfold thicknesses were measured using standard techniques. Other data were collected using a questionnaire that included information about physical activity, television watching, and the amount of exorcise taken during leisure times, family history of diseases related to obesity: social data including family income, parents'education and occupations, eating behaviors; parental weights and heights; and parental activity levels. Childhood overweight was defined as a body mass index at or above the 85th percentile for age and sex. The prevalence of overweight revealed no significant difference between sexes, (24.2% in boys and 22.03% in girls). The risk of childhood overweight was significantly greater if either the mother or the father were overweight. The odds ratio for childhood overweight associated with maternal overweight was 5.045 (94% CI : 3.262-7.801), and 2.727 (95% CI : 1.764-4.218) was the case for parental overweight. Children having a history of hear diseases had higher odds ratios than those who did not. The odds ratios for overweight associated with income were not different. However, a higher odds ratio for overweight was observed in children whose fathers had only an elementary or middle school education than those whore fathers had a high school or college education. Children whose fathers' occupations were service workers or shopkeepers (OR : 3.314, 95% C = 1.851-5.934) or had no occupation (OR = 3.756, 95% CI : 1.898-7.430) had a treater risk of overweight than those whose fathers'were professionals or once workers. The risk of overweight increased in children having more irregular meal times and faster eating times, rather than those having an intake pattern of high energy and sugar containing floods. The amount of exercise taken during leisure times, and daily physical activity showed no difference between overweight and non-overweight children. However, television watching time, especially on weekends, was greater in overweight children than in non-overweight children. Television watching time was positively correlated with BMI, triceps-skin(31d thickness, waist circumference and waist/height ratio. Therefore, television watching was found to be a useful predictor of overweight in children. Television watching in children was negatively related to paternal activity levels, and positively related to parental television watching time. In fact, fathers whose children were overweight were physically less active than fathers whose children were non-overweight. Parents appeared to be a strong influence on their children's physical activity levels. In conclusion, a low family social class, defined on the basis of the father's occupation or education, parental overweight, increased television watching, and unhealthy physical activity levels in parents were all considered risk factors for childhood overweight. Among these, television watching time and lack of physical activity were considered to be the most important risk factors that could be easily modified for the prevention of and intervention in, overweight in children.

• KIPS Transactions on Computer and Communication Systems
• /
• v.3 no.9
• /
• pp.279-292
• /
• 2014

Energy aware server cluster aims to reduce power consumption at maximum while keeping QoS(quality of service) as much as energy non-aware server cluster. In the existing methods of energy aware server cluster, they calculate the minimum number of active servers needed to handle current user requests and control server power mode in a fixed time interval to make only the needed servers ON. When loads change rapidly, QoS of the existing methods become degraded because they cannot increase the number of active servers so quickly. To solve this QoS problem, we classify load change situations into five types of rapid growth, growth, normal, decline, and rapid decline, and apply five different thresholds respectively in calculating the number of active servers. Also, we use a flexible scheme to adjust the above classification criterion for multi threshold, considering not only load change but also the remaining capacity of servers to handle user requests. We performed experiments with a cluster of 15 servers. A special benchmarking tool called SPECweb was used to generate load patterns with rapid change. Experimental results showed that QoS of the proposed method is improved up to the level of energy non-aware server cluster and power consumption is reduced up to about 50 percent, depending on the load pattern.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7494-7500
• /
• 2015

The purpose of this study is to investigate how the customer's attitudes and behavioral responses, depending on the persuasion tactics of salespeople in customer service and meeting point. The tactics of persuasion of customer acceptance and purchase depending on the type of salesperson with proven effectiveness of even comes out to investigate what results according to the purchase form and the customer that the customer consumes gender. Results First, the tactics of persuasion tactics of coercive tactics to mention the loss of a salesman showed that increasing the degree of acceptance than non-coercive tactics to help consumers buy the information provided above. Second, coercive tactics to adjust the effect with respect to the degree of acceptance of the purchase of helping consumers to purchase in the online form has been proven to be more effective than non-coercive tactics case. Third, adjusted for gender effects were proven to help women with respect to the degree of acceptance of a consumer purchases more effective than men. That is, in consumer contacts, the persuasion tactics of salespeople depending on the customer's acceptance and purchasing intention showed that coercive tactics has the more positive impact on online forms and women.

• The KIPS Transactions:PartC
• /
• v.10C no.4
• /
• pp.471-478
• /
• 2003

Traditionally,, analysis, simulation and measurement have all been used to evaluate the performance of network protocols and functional entities that support mobile wireless service. Simulation methods are useful for testing the complex systems which have the very complicate interactions between components. To develop a mobile call simulator which is used to examine, validate, and predict the performance of mobile wireless call procedures must have the teletraffic model, which is to describe the mobile communication environments. Mobile teletraffic model is consists of 2 sub-models, traffic source and network traffic model. In this paper, we analyzed the network traffic data which are gathered from selected Base Stations (BSs) to define the mobile teletraffic model. We defined 4 types of cell location-Residential, Commercial, Industrial, and Afforest zone. We selected some Base Stations (BSs) which are represented cell location types in Seoul city, and gathered real data from them And then, we present the call rate per hour, cail distribution pattern per day, busy hours, loose hours, the maximum number of call, and the minimum number of calls based on defined cell location types. Those parameters are very important to test the mobile communication system´s performance and reliability and are very useful for defining the mobile network traffic model or for working the existed mobile simulation programs as input parameters.