• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• 제8권4호
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• pp.392-400
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• 2003

We used an oxygen microelectrode to measure the vertical profiles of oxygen concentration in sediments located near point sources of organic matter. The measurements were carried out between 13th and 17th May, 2003, in semi-closed bay and coastal sediments in the central part of the South Sea. The measured oxygen penetration depths were extremely shallow and ranged from 1.30 to 3.80 mm. This suggested that the oxidation and reduction reactions in the early diagenesis should be studied at the mm depth scale. In order to estimate the oxygen consumption rate, we applied the one-dimension diffusion-reaction model to vertical profiles of oxygen near the sediment/water interface. Oxygen consumption rates were estimated to be between 10.8 and 27.6 mmol O$_2$ m$\^$-2/ day$\^$-1/(average: 19.1 mmol O$_2$ m$\^$-2/ day$\^$-1/). These rates showed a positive correlation with the organic carbon of the sediments. The corresponding benthic organic carbon oxidation rates calculated using an modified Redfield ratio (170/110) at the sediment/water interface were in the range of 89.5-228.1 mg C m$\^$-2/ day$\^$-1/(average: 158.0 mg C m$\^$-2/ day$\^$-1/). We suggest that these results are maximum values at the presents situation in the bay because the sampling sites were located near point sources of organic materials. This study will need to be carried out at many coastal sites and throughout the seasons to allow an understanding of the mechanisms of eutrophication e.g. the spatial distribution of oxygen consumption within the oxic zone and hypoxic conditions in the coastal sea.

• Korean Journal of Ecology and Environment
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• 제37권3호통권108호
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• pp.344-354
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• 2004

A pilot study was performed from September 2000 to April 2004 to examine the feasibility of the wetland-pond system for the agricultural reuse of reclaimed water. The wetland system was a subsurface flow type, with a hydraulic residence time of 3.5 days, and the subsequent pond was 8 $m^3$ in volume (2 m ${\times}$ 2 m ${\times}$ 2 m) and operated with intermittent-discharge and continuous flow types. The wetland system was effective in treating the sewage; median removal efficiencies of $BOD_5$ and TSS were above 70.0%, with mean effluent concentrations of 27.1 and 16.8 mg $L^{-1}$, respectively, for these constituents. However, they did often exceed the effluent water quality standards of 20 mg $L^{-1}$. Removal of T-N and T-P was relatively less effective and mean effluent concentrations were approximately 103.2 and 7.2 mg $L^{-1}$, respectively. The wetland system demonstrated high removal rate (92 ${\sim}$ 90%) of microorganisms, but effluent concentrations were in the range of 300 ${\sim}$ 16,000 MPN 100 $mL^{-1}$ which is still high for agricultural reuse. The subsequent pond system provided further treatment of the wetland effluent, and especially additional microorganisms removal in addition to wetland-pond system could reduce the mean concentration to 1,000 MPN 100 $mL^{-1}$ from about $10^5$ MPN 100 $mL^{-1}$ of wetland influent. Other parameters in the pond system showed seasonal variation, and the upper layer of the pond water column became remarkably clear immediately after ice melt. Overall, the wetland system was found to be adequate for treating sewage with stable removal efficiency, and the subsequent pond was effective for further polishing. This study concerned agricultural reuse of reclaimed water using natural systems. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, wetland- pond system was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water in rural area.

• Horticultural Science & Technology
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• 제33권1호
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• pp.47-54
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• 2015

This research was conducted to investigate the changes in moisture retention capacities of expanded rice-hull (ERH)-based root media and their influences on the growth of mother and daughter plants in vegetative propagation of 'Seolhyang' strawberry. The proportion of water at the container capacity of ERH medium was in the range of 20 to 23%. This range was lower than the 60 to 66% of strawberry-specialized medium, the 30 to 34% of soil mother material (SMM) and the 30 to 35% of loamy sand. The moisture content of ERH was reduced to 10 to 12% at 8 hours after irrigation, and there were large variations among replications of ERH medium. Among four kinds of root media formulated to contain ERH, the medium of ERH + coir dust (CD) (55 + 45%, v/v) had 26.5 and 32.5% water contents at 20 and 40 days after irrigation to daughter plants, respectively. The m edia o f ERH + sandy loam (S L) and E RH + S MM showed similar trends i n moisture r etention. The pH and EC i n the all root media tested were in the range of 6.7 to 7.1 and 0.03 to $0.08dS{\cdot}m^{-1}$, respectively. The pHs and ECs measured at 20 and 40 days after irrigation were not significantly different in each root medium. Among the root media formulated to contain ERH, the growth of daughter plants was the highest in the treatment of ERH + SL (55 + 45%, v/v). As the blending rate of coir dust was elevated in the ERH + CD media, moisture retention capacity increased gradually, but the growth of daughter plants became worse even though the medium showed higher moisture retention capacity than other root media tested. The growth of roots and aboveground tissues of daughter plants deteriorated in the root media formulated by blending ERH + perlite (PE) at various ratios. The results of this research suggest the optimum formulations of root media and management of moisture content in raising of strawberry daughter plants when ERH is a component of root media.

• Journal of KIISE:Databases
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• 제28권4호
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• pp.742-757
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• 2001

Since database management systems(DBMSS) have limited lock resources, transactions requesting locks beyond the limit mutt be aborted. In the worst carte, if such transactions are aborted repeatedly, the DBMS can become paralyzed, i.e., transaction execute but cannot commit. Lock escalation is considered a solution to this problem. However, existing lock escalation methods do not provide a complete solution. In this paper, we prognose a new lock escalation method, adaptive lock escalation, that selves most of the problems. First, we propose a general model for lock escalation and present the concept of the unescalatable look, which is the major cause making the transactions to abort. Second, we propose the notions of semi lock escalation, lock blocking, and selective relief as the mechanisms to control the number of unescalatable locks. We then propose the adaptive lock escalation method using these notions. Adaptive lock escalation reduces needless aborts and guarantees that the DBMS is not paralyzed under excessive lock requests. It also allows graceful degradation of performance under those circumstances. Third, through extensive simulation, we show that adaptive lock escalation outperforms existing lock escalation methods. The results show that, compared to the existing methods, adaptive lock escalation reduces the number of aborts and the average response time, and increases the throughput to a great extent. Especially, it is shown that the number of concurrent transactions can be increased more than 16 ~256 fold. The contribution of this paper is significant in that it has formally analysed the role of lock escalation in lock resource management and identified the detailed underlying mechanisms. Existing lock escalation methods rely on users or system administrator to handle the problems of excessive lock requests. In contrast, adaptive lock escalation releases the users of this responsibility by providing graceful degradation and preventing system paralysis through automatic control of unescalatable locks Thus adaptive lock escalation can contribute to developing self-tuning: DBMSS that draw a lot of attention these days.

• Journal of KIISE:Databases
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• 제28권4호
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• pp.529-544
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• 2001

Prefetching is an effective method to minimize the number of roundtrips between the client and the server in database management systems. In this paper we propose new notions of the type-level access pattern and the type-level access locality and developed an efficient prefetchin policy based on the notions. The type-level access patterns is a sequence of attributes that are referenced in accessing the objects: the type-level access locality a phenomenon that regular and repetitive type-level access patterns exist. Existing prefetching methods are based on object-level or page-level access patterns, which consist of object0ids of page-ids of the objects accessed. However, the drawback of these methods is that they work only when exactly the same objects or pages are accessed repeatedly. In contrast, even though the same objects are not accessed repeatedly, our technique effectively prefetches objects if the same attributes are referenced repeatedly, i,e of there is type-level access locality. Many navigational applications in Object-Relational Database Management System(ORDBMs) have type-level access locality. Therefore our technique can be employed in ORDBMs to effectively reduce the number of roundtrips thereby significantly enhancing the performance. We have conducted extensive experiments in a prototype ORDBMS to show the effectiveness of our algorithm. Experimental results using the 007 benchmark and a real GIS application show that our technique provides orders of magnitude improvements in the roundtrips and several factors of improvements in overall performance over on-demand fetching and context-based prefetching, which a state-of the art prefetching method. These results indicate that our approach significantly and is a practical method that can be implemented in commercial ORDMSs.

• Journal of Distribution Science
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• 제9권3호
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• pp.83-94
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• 2011

Most domestic companies, with the exclusion of major firms, are reluctant to implement a supply chain management (SCM) network into their operations. Most small- and medium-sized enterprises are not even aware of SCM. Due to the inherent total-systems efficiency of SCM, it coordinates domestic manufacturers, subcontractors, distributors, and physical distributors and cuts down on cost of inventory control, as well as demand management. Furthermore, a lack of SCM causes a decrease in competitiveness for domestic companies. The reason lies in the fundamentality of SCM, which is the characteristic of information sharing, process innovation throughout SCM, and the vast range of problems the SCM management tool is able to address. This study suggests the contemplation and reformation of the current SCM situation by analyzing the SCM strategic plan, discourses and logical discussions on the topic, and a successful case for adapting SCM; hence, the study plans to productively "process" SCM. First, it is necessary to contemplate the theoretical background of SCM before discussing how to successfully process SCM. I will describe the concept and background of SCM in Chapter 2, with a definition of SCM, types of SCM promotional activities, fields of SCM, necessity of applying SCM, and the effects of SCM. All of the defects in currently processing SCM will be introduced in Chapter 3. Discussion items include the following: the Bullwhip Effect; the breakdown in supply chain and sales networks due to e-business; the issue that even though the key to a successful SCM is cooperation between the production and distribution company, during the process of SCM, the companies, many times, put their profits first, resulting in a possible defect in demands estimation. Furthermore, the problems of processing SCM in a domestic distribution-production company concern Information Technology; for example, the new system introduced to the company is not compatible with the pre-existing document architecture. Second, for effective management, distribution and production companies should cooperate and enhance their partnership in the aspect of the corporation; however, in reality, this seldom occurs. Third, in the aspect of the work process, introducing SCM could provoke corporations during the integration of the distribution-production process. Fourth, to increase the achievement of the SCM strategy process, they need to set up a cross-functional team; however, many times, business partners lack the cooperation and business-information sharing tools necessary to effect the transition to SCM. Chapter 4 will address an SCM strategic plan and a case study of LG Electronics. The purpose of the strategic plan, strategic plans for types of business, adopting SCM in a distribution company, and the global supply chain process of LG Electronics will be introduced. The conclusion of the study is located in Chapter 5, which addresses the issue of the fierce competition that companies currently face in the global market environment and their increased investment in SCM, in order to better cope with short product life cycle and high customer expectations. The SCM management system has evolved through the adaptation of improved information, communication, and transportation technologies; now, it demands the utilization of various strategic resources. The introduction of SCM provides benefits to the management of a network of interconnected businesses by securing customer loyalty with cost and time savings, derived through the consolidation of many distribution systems; additionally, SCM helps enterprises form a wide range of marketing strategies. Thus, we could conclude that not only the distributors but all types of businesses should adopt the systems approach to supply chain strategies. SCM deals with the basic stream of distribution and increases the value of a company by replacing physical distribution with information. By the company obtaining and sharing ready information, it is able to create customer satisfaction at the end point of delivery to the consumer.

• Journal of the Korean Society of Food Science and Nutrition
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• 제35권7호
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• pp.945-954
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• 2006

The purpose of this study is to present basic data for an improvement of school foodservice by indentifying students' preference level for school meal menu and assessing students' nutrition intake. The subjects participated in this study were 544 high school students on 1st grade served by self-operated school foodservice in Daegu. The frequency analysis, t-test analysis, and correlation analysis were carried out for the data analysis using SPSS 12.0 program. Based on the results toward students' preference and serving frequency, the most frequently offered food was soup sorts and then followed by the categories of boiled rice, kimchi, broiled food and hard-boiled food. Boiled rice, rice with assorted vegetables, mandu soup, salad and braised beef rib were highly preferred to the students. Male students scored higher preference to the menu related with meats than female students. However, the students' preference and serving frequency on the menu were not correlated significantly in this study. A substantial correlation was found between the degree of preference and the rate of intake (p<0.01). It would be generalized that preferences to menu items strongly sffected the level of intake by students. The nutrient analysis of food intake revealed that both male and female students were not consuming sufficient level of calorie, calcium and vitamin $B_2$. In conclusion, the results indicate that the students' preference is a very important variable influencing the consumption level of meal as well as balanced nutrient intake by students served in school foodservice. Menu planning should be integrated into school foodservice management for quality control. As limited control of the menu may also negatively influence on the food leftovers and ecological issues, professionals related to the school foodservice including administers, educators and dieticians need to check up the students' preference regularly and reflect their perception on the menu planning to improve the quality of school foodservice. The nutrient intake currently provided through school foodservice should be also assessed more thoroughly. These data could be incorporated into continuous quality improvement and strategic planning in school foodservice.

• The Korean Journal of Emergency Medical Services
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• 제13권3호
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• pp.41-58
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• 2009

Objective : The purpose of this study is to identify actual operations and issues of wireless paging system operation for the aged living alone as the end users of wireless paging system primarily in Gwangyang city, and thereby to explore possible advanced and integrated ways to promote social safety network for the aged. Methods : The survey tool used in this study was a structured questionnaire form consisting of question items. The researcher hereof conducted this survey by means of direct visit and interview during two seasons, i.e. from February to August, 2008 and from December 2008 to March 2009, respectively. Results : 1) For general demographic characteristics, it was found that 90.9% of all respondents were women and 61.2% of all respondents were at age 75 to 84. for health conditions, it was found that more than 90% of all respondents often took medicines due to their unhealthy body, and most of respondents suffered from musculoskeletal diseases 79.3% and circulatory diseases 61.6%. for walking capacity, it was found that 45.5% of all respondents used walking aids, and disable respondents (11.5% of all respondents) were represented primarily by those with physical disability (52.6% of disable respondents). for actual use of medical institutions, it was found 47.3% of all respondents relied on local clinics, since they preferred neighborhood hospitals or clinics they can trust for medical care. for social activities and supports, it was found that 43.6% respondents had 'needs for assistance at times' and 33.9% respondents have 'no need for assistance'. And it was found that the major difficulties in living alone at old age were represented primarily by health problems 37.8% and economic difficulties 33.5%. 2) For characteristics related to wireless paging system, it was found that 90.3% respondents used wireless paging system recommended by firemen, and 28.5% respondents used this system. and it was found that 59.6% respondents used this system once, and 85.2% respondents used it because of acute or chronic diseases. more than 90% respondents thought that they knew about wireless paging system and considered themselves safe, but 83.6% respondents didn't attach a remote control on their upper clothes, and even 49.1% respondents turned off the power of wireless paging system due to their concern about electricity bill and noise. 3) It was found that 83.6% respondents felt it necessary to use wireless paging system, and wireless paging users felt more satisfied with using the system than non-users, and 50.7% showed high satisfaction at certain psychological benefits like 'confidence in coping with critical situations' and 'a sense of relief'. In addition, it was found that some respondents who answered that 'they didn't turn off the paging system as they knew how it works' and those who answered that they knew 'how to use it' showed relatively high satisfaction. And some respondents who kept it well and felt it necessary also showed high satisfaction. 4) It was found that the level of satisfaction our respondents felt with using wireless paging system varied significantly availability($x^{2}$ = 12.759, p = .002), psychological advantages($x^{2}$ = 12.174, p = .002), knowledge about how to use system($x^{2}$ = 7.021, p = .016), power on/off($x^{2}$ = 13.221, p = .001), level of knowledge about system($x^{2}$ = 21.002, p = .000), maintenance($x^{2}$ = 9.871, p = .007) and level of necessity($x^{2}$ = 34.939, p = .000) on the statistical basis.

• Journal of Science and Technology Studies
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• 제4권2호
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• pp.67-101
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• 2004

Although the study of citation patterns is an important theme within the sociology of science, due to the fact that it is intimately related to the production, reproduction, and evaluation of knowledge, only sustained theoretical research outlining the differences of citation patterns between the hard and soft sciences has been conducted, and empirical studies nevertheless remain few and far between. The perspectives of institutionalism and constructivism have to attempted to explain different citation patterns between the hard and soft sciences as a contrast between 'what one says' and 'who one is'. Therefore, against this background this study examines the 'theoretical' controversy empirically by comparing the contrasting citation patterns of physics, as a representative of hard science, and sociology, as a representative of soft science. The results, in brief, are as follows: the citaton patterns in physics, as in sociology, vary according to the author's status within the hierarchical employment structure, i. e. whether s/he is a full-time lecturer or not, but diversity of citation patterns according to Ph. D. diploma area is unique to sociology. These results would suggest that the explanation of constructivism is more relevant in explaining variance according to the author's status in the employment hierarchy, but the approach of institutionalism is more appropriate to understanding variance due to Ph. D. diploma area. Furthermore, this implies the complex diversity of the citation patterns between the hard and soft sciences, pointing us to the more qualified conclusion that rather than having to choose between institutionalism and constructivism according to a mutually exclusive either/or logic, these two approaches can in fact be mutually complementary, and these approaches should also be applied piecemeal to different levels of phenomena. In conclusion, this comparative research enables us to assert the following two claims: firstly that physics, as a 'science in society', produces knowledge dependent on social context, and secondly that it also possesses a characteristic that transcends locality from the view of a sociology of knowledge.

• Journal of dental hygiene science
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• 제9권2호
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• pp.169-179
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• 2009

This study aims to present a fundamental data base to figure out the mental and the physical conditions that the dental technicians are facing and ultimately to develop a health care program to deal with their health related problems. To this end, we took an analysis on the health status among the subjects of 895 dental technicians currently working at the dental lab around the nation from January 15 to March 31, 2009 by way or Todai Health Index(THI). Of the average scale point in accordance with 12 scale scores of the physical and the mental subjective symptom, the results revealed that the physical appeals (21.10) were higher than the mental appeals (18.49) and the multiple subjective symptom was marked as 38.44 followed by the mental irritability (25.92). In gender differences, the females proved to be higher than the males in both physical appeals and mental appeals while the physical appeals were dominant in both genders. The physical appeals were higher than the mental appeals with regard to the general characteristics. In the case or the group or age twenties as shown in the physical and mental average scale point, the other groups showed 21.55% of the physical appeals among the married whereas the mental appeals showed the highest point as 18.70 in the unmarried group. In job position, the other groups marked the highest, in working condition, below average group marked the highest, in frequency of break time, none group marked the highest. We drew a conclusion form this study that the dental technicians gained the higher points in the item or the multiple subjective symptom, the menial irritability, and the irregular life. More research on th is phenomena should be followed along with the development of various and practical health care programs to promote the health or dental technicians.