• Journal of The Korean Society of Grassland and Forage Science
• /
• v.40 no.2
• /
• pp.111-116
• /
• 2020

This study was conducted to determine the maintenance energy requirements of growing goats in order to establish an appropriate energy benefit system, to reduce feed costs and improve livestock productivity of goat farmers, and to present basic data for detailed specifications afterwards. This experiment was conducted as a group specification test for a total of 3 months, with 32 goats of three months age and conducted by four treatments with different energy levels (T1: NRC+0%, T2: NRC+10%, T3: NRC+20%, and T4: NRC+30%). The average daily gain was the highest in the treated with NRC + 10% of the energy level of the experimental diet, and the feed conversion ratio was in the range of 6.3 g to 7.3 g in the group feeding experiment. Although there was no significant difference in digestibility between treatments, the digestibility of dry matter, crude protein, and crude fat was higher in T2 treated with NRC + 10% than the other treatments. Through the regression equation of the values of MEI and ADG obtained through the experiment (Y=0.5439X+111.51, R²=0.712), the maintenance energy requirement of the goat in the growing period was estimated to be 111.51 kcal/kgBW^0.75.

• Journal of the Korean Geographical Society
• /
• v.28 no.2
• /
• pp.148-162
• /
• 1993

There is much speculation that modern capi-talist society is undergoing fundamental and qualitative chnge towards flexible specialization. The purpose of this study is to examine this hypothesis. This paper focusses on: the idea of flexible specialization; the significance of this transition; industrial district; and the implicati-ons of this new production system for Korean industrial space. Main arguments of this study are as follows: First, as all different groups of researchers apply the idea of flexible specialization according to their own specifications, the current debate on this topic is not much fruitful. Not surpri-singly, the concept of flexible specialization has overlapped with subocontracting. This intergration of subcontracting into flexible specialization systems, however, is inappropriate because the two concepts have different historical contexts. The other cause of this controversy is its inherent weekness, conceptual ambiguity. Thus, today's flexibility becomes tomorrow's rigidity. Secondly, transition towards flexible speciali-zation has only been partially achieved even in advanced capitalist countries. The application of dualistic explanatory framework, such as rigidity versus flexibiity, mass production versus small-lot multi-product production, and de-skilling versus re-skilling, has resulted in great exaggeration of the transformation, from Fordism to post-Fordism. There is no intermediary part between two places. Considering that the workers allocated to the Fordist mass production assembly line are not as large as one might imagine, the shift from mass to flexible production has only limited implications for the transformation of capitalist economy. Thirdly, 'industrial district' contorversy has contributed to highlighting the importance of small firms and areas as production space. The agglomeration of small firms in specific areas is common in Korea, but it is quite different from the industrial district based on flexible specialization. The Korean phenomenon stems from close interactions with its major parent firm rather than interactions between flexible, specialized, autonomous and technology-intensive smll firms. Most Korean subcontractors are still low-skilled, labour-intensive, and heavily dependent on their mojor parent firms. Thus, the assertion that the Seoul Metropolitan Area adopts flexible specialization has no base. Fourthly, the main concern of flexible speciali zation is small firms. However, the corporate organization that needs product diversification and technological specialization is oligopolistic large corporations typified by multinational corporations. It is because of this that most of these organizations are adoptiong Fordist mass production methods. The problem of product diversification will be resolved naturally if economic internationalization progresses further. What is more important for business success is the quality and price competitiveness of firms rather than product diversification. Lastly, in order to dispel further misunderst-anding on this issue, it is imparative that the conceptual ambiguity is resolved most urgently. This study recommends adoption of more speci-fied and direct terminology (such as, factory automation, computer design, out-sourcing, the exploitation of part-time labor, job redesign) rather than that of ideological ones (such as, Taylorism, Fordism, neo-Taylorism, neo-Fordism, post-fordism, flexible specialization, peripheral post-Fordism). As the debates on this topic just started, we still have long way to go until consensus is reached.

• KEPCO Journal on Electric Power and Energy
• /
• v.1 no.1
• /
• pp.39-46
• /
• 2015

A outdoor termination installed at the outdoor substation is required to connect undergroud cables and overhead transmission lines. The joint box for AC transmission system is already developed and widely used to interconnect overhead and undergroud systems. But the development of the joint box for DC transmission system was only introduced from China and Japan, but theire developemnt staus and core technologies were not fully reported. In order to implement HVDC systems connecting ovehead transmission lines and undergroud cables, a outdoor termination should be developed, but the detailed specifications and information of this device were not reported. It is estimated that the development of the joint box for DC environment has some technical obstacles including insulating materials, electric field mitigation, thermal temperature rise, and space charge accumuations. Among this, the most important one is the DC elctrical insualtion design. Therefore, in order to investigate the DC elctrical insualton design of outdoor termination, the design of AC slip-on type outdoor termination is reffered, and DC electric field analysis performed to verify the possiblity of application of AC joint box into DC joint box. Especially for DC electric field analysis, temperature rise of insualting materials of a joint box was considered, because the conductivity of materials could be changed due to temperature rise. Furthermore, DC electric field analysis considering transinet state, and polarity reversal state were also investigated to verify which state is the most severe condition for the DC joint box. From the simualtion resulsts, it was shown that the value and the position of maximum electric field was obtained comparing AC state, DC state without temperaure rise, and DC state with temperaure rise. And it was confimred that severe DC electric field was observed considing temperaure rise. Finally, in order to reduce DC eletric field intensifation, different configuration of the joint box was applied and it was not possible to obtain satisfactory results. It means that the slight change of configuration of AC joint box was not the suitable soluton for DC joint box. It is essential to establish novel DC insulaton design skills and method for DC joint box to commercialze this product in the near future.

• The Journal of Engineering Geology
• /
• v.18 no.4
• /
• pp.447-457
• /
• 2008

Laboratory tests for single plane sliding were conducted using the model rock slope to investigate the cut slope deformability and failure mechanism due to combined effect of engineering characteristics such as angle of sliding plane, water force, joint roughness and infillings. Also the possibility of prediction of slope failure through displacement monitoring was explored. The joint roughness was prepared in forms of saw-tooth type having different roughness specifications. The infillings was maintained between upper and lower roughness plane from zero to 1.2 times of the amplitude of the surface projections. Water force was expressed as the percent filling of tension crack from dry (0%) to full (100%), and constantly increased from 0% at the rate of 0.5%/min and 1%/min upto failure. Total of 50 tests were performed at sliding angles of $30^{\circ}$ and $35^{\circ}$ based on different combinations of joint roughness, infilling thickness and water force increment conditions. For smooth sliding plane, it was found that the linear type of deformability exhibited irrespective of the infilling thickness and water force conditions. For sliding planes having roughness, stepping or exponential types of deformability were predominant under condition that the infilling thickness is lower or higher than asperity height, respectively. These arise from the fact that, once the infilling thickness exceeds asperities, strength and deformability of the sliding plane is controlled by the engineering characteristics of the infilling materials. The results obtained in this study clearly show that the water force at failure was found to increase with increasing joint roughness, and to decrease with increasing filling thickness. It seems possible to estimate failure time using the inverse velocity method for sliding plane having exponential type of deformability. However, it is necessary to estimate failure time by trial and error basis to predict failure of the slope accurately.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.9
• /
• pp.4602-4609
• /
• 2013

In summer and winter, the difference between the temperature during the day and that during the night is high, which leads to various problems during concrete placement, such as cracks and defects in the concrete as well as low durability and strength. Although nuclear power plant concrete is widely used for placement in all seasons, particular attention must be paid to its quality during the summer. Therefore, we evaluated the effects of a cooling method for mixing water, which is a commonly used hot weather precooling method, and the use of a retarder, on the characteristics of Nuclear Power Plant concrete. In the cooling method for mixing water, cold water at 5 was used, with 50% of the water content consisting of ice flakes. The effects of using a retarder were evaluated by reviewing the characteristics of the cement at the unset stage and after hardening. To evaluate the characteristics of the unset cement, we measured the slump, air volumes, setting times, and pressure strengths after hardening. Furthermore, we measured the heat of hydration at different temperatures; the loss of heat was minimized using insulation. Both the slump time and the complete ageing time of the air volume were found to be 120 min at $20^{\circ}C$ and 40 min at $40^{\circ}C$. In the case when the cooling method for mixing water was used and in the case when a retarder was used, the initial and final sets by penetration resistance were delayed, and the delay decreased with increasing air temperature. For the heat of hydration, the cooling method for mixing water not only lowered the maximum temperature but also delayed its attainment. However, the use of a retarder had no effect on the maximum temperature. Moreover, in the early ages (e.g., 3 and 7 days), the pressure strength of the concrete was lower than that of plain cement. However, the strength of 28-day concrete met the standard construction specifications.

• Journal of Korea Water Resources Association
• /
• v.53 no.8
• /
• pp.627-636
• /
• 2020

Debris flow disasters primarily occur in mountainous terrains far from cities. As such, they have been underestimated to cause relatively less damage compared with other natural disasters. However, owing to urbanization, several residential areas and major facilities have been built in mountainous regions, and the frequency of debris flow disasters is steadily increasing owing to the increase in rainfall with environmental and climate changes. Thus, the risk of debris flow is on the rise. However, only a few studies have explored the characteristics of flooding and reduction measures for debris flow in areas designated as steep slopes. In this regard, it is necessary to conduct research on securing independent disaster prevention technology, suitable for the environment in South Korea and reflective of the topographical characteristics thereof, and update and improve disaster prevention information. Accordingly, this study aimed to calculate the amount of debris flow, depending on disaster prevention performance targets for regions designated as steep slopes in South Korea, and develop an independent model to not only evaluate the impact of debris flow but also identify debris barriers that are optimal for mitigating damage. To validate the reliability of the two-dimensional debris flow model developed for the evaluation of debris barriers, the model's performance was compared with that of the hydraulic model. Furthermore, a 2-D debris model was constructed in consideration of the regional characteristics around the steep slopes to analyze the flow characteristics of the debris that directly reaches the damaged area. The flow characteristics of the debris delivered downstream were further analyzed, depending on the specifications (height) and installation locations of the debris barriers employed to reduce the damage. The experimental results showed that the reliability of the developed model is satisfactory; further, this study confirmed significant performance degradation of debris barriers in areas where the barriers were installed at a slope of 20° or more, which is the slope at which debris flows occur.

• Asia pacific journal of information systems
• /
• v.24 no.4
• /
• pp.611-635
• /
• 2014

Information systems (IS) have become ubiquitous and changed every aspect of how people live their lives. While some IS have been successfully adopted and widely used, others have failed to be adopted and crowded out in spite of remarkable progress in technologies. Both the technology acceptance model (TAM) and the IS Success Model (ISSM), among many others, have contributed to explain the reasons of success as well as failure in IS adoption and usage. While the TAM suggests that intention to use and perceived usefulness lead to actual IS usage, the ISSM indicates that information quality, system quality, and service quality affect IS usage and user satisfaction. Upon literature review, however, we found a significant void in theoretical development and its applications that employ either of the two models, and we raise research questions. First of all, in spite of the causal relationship between intention to use and actual usage, in most previous studies, only intention to use was employed as a dependent variable without overt explaining its relationship with actual usage. Moreover, even in a few studies that employed actual IS usage as a dependent variable, the degree of actual usage was measured based on users' perceptual responses to survey questionnaires. However, the measurement of actual usage based on survey responses might not be 'actual' usage in a strict sense that responders' perception may be distorted due to their selective perceptions or stereotypes. By the same token, the degree of system quality that IS users perceive might not be 'real' quality as well. This study seeks to fill this void by measuring the variables of actual usage and system quality using 'fact' data such as system logs and specifications of users' information and communications technology (ICT) devices. More specifically, we propose an integrated research model that bring together the TAM and the ISSM. The integrated model is composed of both the variables that are to be measured using fact as well as survey data. By employing the integrated model, we expect to reveal the difference between real and perceived degree of system quality, and to investigate the relationship between the perception-based measure of intention to use and the fact-based measure of actual usage. Furthermore, we also aim to add empirical findings on the general research question: what factors influence actual IS usage and how? In order to address the research question and to examine the research model, we selected a mobile campus application (MCA). We collected both fact data and survey data. For fact data, we retrieved them from the system logs such information as menu usage counts, user's device performance, display size, and operating system revision version number. At the same time, we conducted a survey among university students who use an MCA, and collected 180 valid responses. A partial least square (PLS) method was employed to validate our research model. Among nine hypotheses developed, we found five were supported while four were not. In detail, the relationships between (1) perceived system quality and perceived usefulness, (2) perceived system quality and perceived intention to use, (3) perceived usefulness and perceived intention to use, (4) quality of device platform and actual IS usage, and (5) perceived intention to use and actual IS usage were found to be significant. In comparison, the relationships between (1) quality of device platform and perceived system quality, (2) quality of device platform and perceived usefulness, (3) quality of device platform and perceived intention to use, and (4) perceived system quality and actual IS usage were not significant. The results of the study reveal notable differences from those of previous studies. First, although perceived intention to use shows a positive effect on actual IS usage, its explanatory power is very weak ($R^2$=0.064). Second, fact-based system quality (quality of user's device platform) shows a direct impact on actual IS usage without the mediating role of intention to use. Lastly, the relationships between perceived system quality (perception-based system quality) and other constructs show completely different results from those between quality of device platform (fact-based system quality) and other constructs. In the post-hoc analysis, IS users' past behavior was additionally included in the research model to further investigate the cause of such a low explanatory power of actual IS usage. The results show that past IS usage has a strong positive effect on current IS usage while intention to use does not have, implying that IS usage has already become a habitual behavior. This study provides the following several implications. First, we verify that fact-based data (i.e., system logs of real usage records) are more likely to reflect IS users' actual usage than perception-based data. In addition, by identifying the direct impact of quality of device platform on actual IS usage (without any mediating roles of attitude or intention), this study triggers further research on other potential factors that may directly influence actual IS usage. Furthermore, the results of the study provide practical strategic implications that organizations equipped with high-quality systems may directly expect high level of system usage.

• Journal of Internet Computing and Services
• /
• v.16 no.5
• /
• pp.29-38
• /
• 2015

The Energy Storage System stores electricity for later use. This system can store electricity from legacy electric power systems or renewable energy systems into a battery device when demand is low. When there is high electricity demand, it uses the electricity previously stored and enables efficient energy usage and stable operation of the electric power system. It increases the energy usage efficiency, stabilizes the power supply system, and increases the utilization of renewable energy. The recent increase in the global interest for efficient energy consumption has increased the need for an energy storage system that can satisfy both the consumers' demand for stable power supply and the suppliers' demand for power demand normalization. In general, an energy storage system consists of a Power Conditioning System, a Battery Management System, a battery cell and peripheral devices. The specifications of the subsystems that form the energy storage system are manufacturer dependent. Since the core component interfaces are not standardized, there are difficulties in forming and operating the energy storage system. In this paper, the design of the profile structure for energy storage system and realization of private profiling system for energy storage system is presented. The profiling system accommodates diverse component settings that are manufacturer dependent and information needed for effective operation. The settings and operation information of various PCSs, BMSs, battery cells, and other peripheral device are analyzed to define profile specification and structure. A profile adapter software that can be applied to energy storage system is designed and implemented. The profiles for energy storage system generated by the profile authoring tool consist of a settings profile and operation profile. Setting profile consists of configuration information for energy device what composes energy saving system. To be more specific, setting profile has three parts of category as information for electric control module, sub system, and interface for communication between electric devices. Operation profile includes information in relation to the method in which controls Energy Storage system. The profiles are based on standard XML specification to accommodate future extensions. The profile system has been verified by applying it to an energy storage system and testing charge and discharge operations.

• Journal of Food Hygiene and Safety
• /
• v.29 no.4
• /
• pp.322-326
• /
• 2014

According to Centers for Disease Control and Prevention (CDC, USA) recently it was reported that the children (< 5 year-old children) were more susceptible to Foodborne-illness. Confectionery products should be strictly controlled because they are children-preferred foods. Ministry of Food and Drug Safety (MFDS, South of Korea) tried to monitor contamination of organisms in confectionery products (such as biscuits, candies, chewing gums and ice candies) distributed in South Korea. MFDS evaluated the levels of indicator organisms: total aerobic bacteria, coliforms, Escherichia coli as well as the levels of food-borne illness organisms: Staphylococcus aureus, Bacillus cereus, Clostridium perfringens. Experimental plans for microbiological test were in accordance with the International Commission on Microbiological Specifications for Food (ICMSF). For this study, 1,005 samples were collected and from Seoul and Gyeongin region, South Korea. The average level of total aerobic bacteria in 1,005 samples was 1.7 log Colony Forming Unit(CFU)/g and the detection rate was 26.8%. The average level of Bacillus cereus was detected in 1.7 log CFU/g and the rate was 0.9%. There was no detection of coliforms, Escherichia coli, Staphylococcus aureus and Clostridium perfringens. The results of this study will be provided as the basic data to set the reasonable microbiological criteria of Korea Food Code.

• Journal of Food Hygiene and Safety
• /
• v.33 no.2
• /
• pp.124-130
• /
• 2018

The Ministry of Food and Drug Safety (MFDS) is amending its test methods for the use of health functional foods (dietary food supplement), in order to establish regulatory standards and specifications in Korea. In this regard, we continue to pursue and perform our research on the analytical method development for the items being researched and reviewed. In this study, we have developed a sensitive and selective test method that could simultaneously separate and determinate six major bioactive flavonolignans in silymarin, which are based on the use of a liquid chromatographic-tandem mass spectrometry (LC-MS/MS). The standard calibration curves presented a linearity effect with the correlation coefficient ($r^2$) > 0.999. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of $0.3{\sim}9.0{\mu}g/L$ and $0.8{\sim}27.3{\mu}g/L$, respectively. The recovery results ranged between 96.2~98.6% at 3 different concentration levels, and its relative standard deviations (RSDs) were less than 5% as noted in this study. The proposed analytical method was characterized with a noted high resolution of the individual silymarin constituents, and the assay was fully validated as well. Our research can provide a significant scientific evidence that can be useful to amend the silymarin test method for the Health Functional Food Code.