• Journal of Korean Society on Water Environment
• /
• v.20 no.3
• /
• pp.197-205
• /
• 2004

Batch test methods have developed for a long time to measure kinetic and stoichiometric parameters which are required to perform steady state design and mathematical modelling of activated sludge processes. However, at various So/Xo ratios, abnormal behaviors of ordinary heterotrophic organism in batch tests have been reported in many researches. Thus, in this research, abnormal behaviors of heterotrophs in batch tests were investigated at various So/Xo conditions by measuring and interpreting oxygen utilization rate. As So/Xo ratio increased, the calculated values of maximum specific growth rates, ${\mu}_{H,max}$ and $K_{MP,max}$, increased. However, at a certain point of So/Xo (around 10mgCOD/mgMLAVSS), ${\mu}_{H,max}$ and $K_{MP,max}$ values started to decrease. According to this observation, three prominent behaviours of heterotrophs were identified at various So/Xo conditions. (1) At low So/Xo region (below 5 mgCOD/mgMLAVSS), the oxygen utilization rate of heterotrophs in batch tests were almost stable and consequently yielded lower maximum specific growth rate. (2) At high So/Xo region (up to 5~10 mgCOD/mgMLAVSS), oxygen utilization rate incresed sharply with time and indicated more upward curvature than the predicted OUR with conventional activated sludge model, which consists of single hetetrotrophs group. Thus, in this region, competition model of two organisms, fast-grower and slow-grower, seemed to be appropriate. (3) At extremely high So/Xo region (over 10mgCOD/mgMLAVSS), significant oxygen utilization rate was still observed even after depletion of readily biodegradable COD. This might be caused by retarded utilization of intermediates which were generated by self inhibition mechanism in the process of RBCOD uptake.

• Journal of Ecology and Environment
• /
• v.45 no.4
• /
• pp.313-327
• /
• 2021

Background: Citizen science is becoming a mainstream approach of baseline data collection to monitor biodiversity and climate change. Dragonflies (Odonata) have been ranked as the highest priority group in biodiversity monitoring for global warming. Ischnura senegalensis Rambur has been designated a biological indicator of climate change and is being monitored by the citizen science project "Korean Biodiversity Observation Network." This study has been performed to understand changes in the distribution range of I. senegalensis in response to climate change using citizen science data in South Korea. Results: We constructed a dataset of 397 distribution records for I. senegalensis, ranging from 1980 to 2020. The number of records sharply increased over time and space, and in particular, citizen science monitoring data accounted for the greatest proportion (58.7%) and covered the widest geographical range. This species was only distributed in the southern provinces until 2010 but was recorded in the higher latitudes such as Gangwon-do, Incheon, Seoul, and Gyeonggi-do (max. Paju-si, 37.70° latitude) by 2020. A species distribution model showed that the annual mean temperature (Bio1; 63.2%) and the maximum temperature of the warmest month (Bio5; 16.7%) were the most critical factors influencing its distribution. Future climate change scenarios have predicted an increase in suitable habitats for this species. Conclusions: This study is the first to show the northward expansion in the distribution range of I. senegalensis in response to climate warming in South Korea over the past 40 years. In particular, citizen science was crucial in supplying critical baseline data to detect the distribution change toward higher latitudes. Our results provide new insights on the value of citizen science as a tool for detecting the impact of climate change on ecosystems in South Korea.

• IE interfaces
• /
• v.17 no.4
• /
• pp.472-481
• /
• 2004

In this paper, we propose a linear programming model of supply planning process for the supply chain collaboration strategy of a company. The amount of its supplying quantity relies on outsourcing suppliers heavily. Conversely, the revenues of those suppliers are highly dependent on the supplying quota from the supply network planning of the company. In order to keep the supply stable through collaboration, the company builds such a policy to guarantee the fairness on revenue between the supplies. For this, the supply network plan should keep the capacity utilization ratio even for all the suppliers. But the production capacities are different and the distribution of molds is disproportional through suppliers, so the supply network plan is not easily established with simple arithmetic processes. Therefore, we developed the linear programming model with those target function and constraints minimizing the costs for holding inventory and penalty of delayed delivery, simultaneously guaranteeing the even capacity utilization through suppliers. The proposed model has been applied to real case and the evaluation for the planning result from the model would be followed in order to make sure that our model guarantee on extracting the supply network plan subordinated to the policy. Also we mention about further studies for improvement of the model.

• Knowledge Management Research
• /
• v.16 no.4
• /
• pp.169-190
• /
• 2015

The status of small and medium-sized enterprises has been changed into more independent business entities rather than simply subcontractor so that the utilization of specialized knowledge has been much more necessary for the survival in the market. However, small and medium-sized enterprises, it is difficult to sufficient investment in knowledge services due to limited resources relative to large enterprises and demand for knowledge services business of government support is growing. For this reason, it is important to measure accurately the demand for knowledge services of small and medium-sized enterprises in knowledge management for effective utilization of knowledge service. In this study, we analyzed previous studies on small and medium-sized enterprises knowledge services that can be utilized in a comprehensive way. As a result, we developed knowledge service needs assessment model based on five critical success factors for continual growth and 12 types of knowledge service. This model has been modified and supplemented through expert meeting using delphi research method and topic modeling analysis using secondary data. This study is attempted to appropriately measure necessary knowledge services for small and medium-sized enterprises so that generated the evaluation model of knowledge service demands, comprehensively dealing with core knowledge services for many kinds of business entities. It is expected that the developed model will be a useful tool to understand and evaluate knowledge services demands of enterprises.

• Journal of Distribution Science
• /
• v.14 no.11
• /
• pp.75-82
• /
• 2016

Purpose - In order for actively pursuing medium and long term policies of Gangwon region to be effectively and efficiently driven, efficacious and practical development strategies are needed. In terms of regional revitalization in most regions that are dependent on the primary industry like Gangwon-do Province, the maintaining of local community becomes difficult and there are limitations on the support from the central government and local governments. Therefore, local communities need to implement measures not only to be financially independent but also maintain and activate themselves. And community business can be adopted to be a proper strategy to cope with this change. This study drew importance of a community business model appropriate for Gangwon-do region to figure out success factors. Research design, data, and methodology - This study aimed to come up with importance of community business model for Gangwon-do region by using AHP Method. AHP Method, which was developed by Professor Saaty in 1970', is a methodology to simplify complex problems for a rational decision making. A survey targeting related public officials and expert group was carried out and a total of 30 questionnaires were collected for the analysis. Results - Analysis model used in this study was to prioritize community business models of Gangwon-do region. The second hierarchy was divided according to local restoration type, local resource utilization type, environment improvement type, and life support type. The third hierarchy consisted of 5 items such as network, the middle structure, program, government support, and human resources to measure each importance. As a result, in the second hierarchy, local resource utilization type had the highest importance. In the third hierarchy, the middle structure had the highest importance, followed by government support, program, network, and human resources. Collectively, the results suggested that important critical factors of community business model of Gangwon-do region was the importance of local resource utilization model and the middle structure. Conclusions - Not only should projects that are already operating in the region but next community business projects that are planning in the Gangwon-do region should be practically operated in view of the importance and the models derived from this study.

• Journal of Society of Preventive Korean Medicine
• /
• v.27 no.1
• /
• pp.17-27
• /
• 2023

Objectives : This study aimed to analyze the factors influencing Korean medical utilization among persons with unmet healthcare needs. Methods : This study utilized Korea Health Panel data in 2019, with 10,771. We performed a t-test and ANOVA on the difference in general characteristics between Korean medical utilization and unmet healthcare needs. Logistic regression analysis and generalized linear model analysis were conducted to analyze on factors affecting the Korean medical utilization by people with unmet healthcare needs. Results : Among people with unmet healthcare needs, the variables influencing Korean medical utilization were western medical utilization, gender, education level, musculoskeletal disease, and other chronic diseases. The more people with unmet healthcare needs, the more likely they were to use Korean medicine. As a result of logistic regression analysis, the influencing factors on Korean medical utilization were analyzed for people with unmet healthcare needs, and the higher the household income, the more musculoskeletal diseases, and the higher the probability of using Korean medicine. Conclusions : Korean medicine has a large proportion of musculoskeletal disease, so it was found that musculoskeletal diseases have an impact. In addition, considering that household income is an important factor in the influencing factor of unmet healthcare needs, it is necessary to increase the use of Korean medicine by those with low household incomes.

• Health Policy and Management
• /
• v.3 no.2
• /
• pp.159-176
• /
• 1993

The utilization of outpatient care services involves two steps of sequential decisions. The first step decision is about whether to initiate the utilization and the second one is about how many more visits to make after the initiation. Presumably, the initiation decision is largely made by the patient and his or her family, while the number of additional visits is decided under a strong influence of the physician. Implication is that the analysis of the outpatient care utilization requires to specify each of the two decisions underlying the utilization as a distinct stochastic process. This paper is concerned with the number of physician visits, which is, by definition, a discrete variable that can take only non-negative integer values. Since the initial visit is considered in the analysis of whether or not having made any physician visit, the focus on the number of visits made in addition to the initial one must be enough. The number of additional visits, being a kind of count data, could be assumed to exhibit a Poisson distribution. However, it is likely that the distribution is over dispersed since the number of physician visits tends to cluster around a few values but still vary widely. A recently reported study of outpatient care utilization employed an analysis based upon the assumption of a negative binomial distribution which is a type of overdispersed Poisson distribution. But there is an indication that the use of Poisson distribution making adjustments for over-dispersion results in less loss of efficiency in parameter estimation compared to the use of a certain type of distribution like a negative binomial distribution. An analysis of the data for outpatient care utilization was performed focusing on an assessment of appropriateness of available techniques. The data used in the analysis were collected by a community survey in Hwachon Gun, Kangwon Do in 1990. It was observed that a Poisson regression with adjustments for over-dispersion is superior to either an ordinary regression or a Poisson regression without adjustments oor over-dispersion. In conclusion, it seems the most approprite to assume that the number of physician visits made in addition to the initial visist exhibits an overdispersed Poisson distribution when outpatient care utilization is studied based upon a model which embodies the two-part character of the decision process uderlying the utilization.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.05a
• /
• pp.496.2-496.2
• /
• 2004

• Computational Structural Engineering
• /
• v.37 no.1
• /
• pp.17-27
• /
• 2024

• Journal of Preventive Medicine and Public Health
• /
• v.29 no.2 s.53
• /
• pp.311-329
• /
• 1996

This study was designed to compare the level of medical utilization between the urban and rural areas of Korea and to explain the differences between the two regions. Data from the National Health Interview Survey performed by the Korean Institute of Health & Social Affairs in 1992 were used for this study utilizing a sample size of 21,841 people. The level of medical utilization such as the number of physician visits and the number of hospital admissions was compared between the regions with ANOVA. Various determinants for medical use were also compared by univariate analysis. Statistical models which included enabling factors, predisposing factors, need factors and region were constructed for bivariate analysis in order to further elucidate the level of medical utilization. The results were as follows: 1. There was greater medical use, both in terms of physician visits and inpatient care in the rural areas in spite of insufficient health resources. The particular reasons for higher medical utilization in rural areas were attributed to a higher number of initial physician visits as well as a longer the length of stay per hospital admission. Therefore, indicators representing the degree of met need (utilization/need) showed no significant difference between rural and urban areas in spite of the fact that the medical need is larger in rural areas. 2. Use of public health facilities received a significant portion of physician visits in the rural area. The government's effort to enhance primary health care through health centers, health subcenters and the nurse practitioner's post in rural areas has contributed to the increase of access to medical care in the rural areas. 3. There were some differences in the socio-demographic characteristics between two regions ; There were more elderly people over the age of 65: unstable marital status, less education and lower incomes also characterized the rural areas. Therefore, among rural people, there were more predisposing factors for medical use. Additionaly, need factors such as poor self-reported health status and high morbidity level were also high in the rural area. 4. In contrast it was learned that, the supply of health resources was mostly concentrated in the urban areas except for public health facilities. Therefore, geographical access to medical care was lower in the rural area both in terms travel time and travel cost. 5. The coefficient of the region variable was insignificant in the regression model which controlled the supply factor only. However, utilization was significantly higher in urban areas if the model included predisposing factors and need factors in addition to the supply factor. The results were interpreted as rural people have greater medical needs.