• Asia pacific journal of information systems
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• v.19 no.3
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• pp.51-67
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• 2009

Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

• KDI Journal of Economic Policy
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• v.12 no.1
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• pp.111-125
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• 1990

For the last several years, considerable criticism has been leveled against Korea's exchange rate management. While Korea was designated a currency manipulator by the U.S., domestically it is often complained that the won/dollar rate did not adequately reflect changes in Korea's export competitiveness and fluctuations in the exchange rates of major currencies. In view of this situation, Korea changed its exchange regime at the beginning of March this year from the dual currency basket system to a more flexible one, called a "market average rate regime". Under this new regime, the won rate is determined in the exchange market based upon the supply of and demand for foreign exchange and is allowed to freely fluctuate each day within a + 0.4 % range. This paper, first, seeks to evaluate Korea's exchange rate management under the dual basket regime of the 1980s, and then to construct an optimal currency basket for the won which could provide a proper indicator for exchange market intervention under the new market average rate regime. The analysis of fluctuations in the real effective exchange rate (REER) of the won indicates that the won rates in the 1980s failed not only to offset changes in relative prices between home and trading partner countries, but also to properly respond to variations in major exchange rates as further evidenced by sizable fluctuations in the nominal effective rates of the won. In other words, the currency basket regime which was adopted in 1980 for the stabilization of the REER of the won has not been operated properly, mainly because authorities often resorted to policy considerations in determining the won's rate. In the second part of the paper, an optimal currency basket for Korea is constructed, designed to minimize the fluctuations in the REER of the won without including policy considerations as a factor. It is recognized, however, that both domestic and foreign price data are not available immediately for the calculation of the REER. For this problem, the approach suggested by Lipschitz (1980) is followed, in which optimal weights for currencies in the basket are determined based upon the past correlation between price and exchange rates. When the optimal basket is applied to Korea since the mid-80s, it is found that the REER of the won could have been much more stable than it actually was. We also argue for the use of variable weights rather than fixed ones, which would be determined by the changing relationship between exchange rates and relative prices. The optimal basket, and the optimal basket exchange rate based on that basket, could provide an important medium- or long-term reference for proper exchange market intervention under the market average rate regime, together with other factors, such as developments in the current account balance and changes in productivity.

• Korean Journal of Construction Engineering and Management
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• v.12 no.6
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• pp.65-78
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• 2011

Construction business, which is complex and long-term business, requires accurate estimation and verification in construction costs and payment procedure from project planning to the completion of construction phase. And more importantly, it is necessary to investigate and determine the risk factors related to construction costs during the entire process including design planning, construction drawings, and quantity calculating. But, currently, it is not seem to be adequate to cope with the risk and increased construction costs against the operational budget in terms of actual costs when screening and estimating the bidding cost of public apartment. Therefore, this study selected and analyzed 40 sites' report of construction completion account from 2004 to 2010 focused on the adequacy on the modification of contract and design planning and on the complication of the budget in the beginning of the project. This study deducted various risk causes and results by analyzing actual costs according to year, architectural area, region, construction cost and sale/lease classification. We could find out construction risk according to annual variation of government policy and economy, and also deducted risk items by construction characteristic according to region and architectural area. Study result, we first found out the problems of lowest price award system according to the construction costs. The weight of the cost increase risk was analyzed that subcontract and material costs are very high. Roof and tile work were analyzed highly in subcontract cost risk and reinforcing bar and cement were analyzed highly in material cost risk, among direct construction cost. Finally, this study results could be used in comparing the categories of the construction costs made by specific construction process, belonging to the construction costs, with the operational budget made in the beginning of the project that can enable to grasp unpredictable risks over the construction costs and making quantitative analysis for it through analyzing the range of fluctuation and variations led by the fluctuations in the actual construction costs.

• KDI Journal of Economic Policy
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• v.32 no.2
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• pp.171-216
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• 2010

With the payment and settlement systems becoming more and more complex and interconnected, the issue of their interdependency rises as an important academic issue as well as a policy topic. This study examines causes, forms, and risk management of interdependencies of payment and settlement systems in Korea, and presents their current situation. By way of simulations using BOF-PSS2 developed by the Bank of Finland, we quantify the effects of an operational disruption on the payment and settlement systems so as to figure out the degree of interdependency. As a result, the secondary round effect reaches up to ￦13.6 trillion a day, which amounts to 7.8% of the daily settlement value. Furthermore, if we also consider the amount of direct operational disruption, the volume of operational disruption occupies 22.3% of total value of the daily settlement, evidencing that the interdependencies of the payment and settlement systems in Korea is enormously widespread. The secondary round effects are found to be more severe with security companies rather than with banks, and to be more depended upon when it is perceived rather than it actually happens. In case that we expand the liquidity to include cash holdings and deposits as assets, the secondary round effect dramatically decreases in all types of financial institutions while foreign banks account for more share of all the secondary round effects increases. Based on these results, we suggest various policy tasks and directions to improve the risk management of settlement systems: expansion of off-setting settlements, introduction of a new settlement system for securities transactions, rapid provision of liquidity to financial institutions, more effective monitoring on participant institutions, and intensified information sharing and cooperation among the systems.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.376-387
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• 2019

Melons are mostly grown in soil, but it is susceptible to damage due to injury by continuous cropping such as Fusarium wilt and root rot. Hydroponic cultivation system can overcome the disadvantages of soil cultivation with precise nutrition management and a clean environment. When using the coir substrate, the most environmentally friendly organic substrate used for hydroponics, it is analyzed how the growth and fruit quality of the melon depends on the ratio of chips and dust and the amount of irrigation. The purpose of this study was to provide the basic data of melon hydroponics when cultivated in spring. The two types of the coir substrates used in the experiments were chip and dust ratios of 3 :7 and 5 : 5 respectively. The substrate with high dust ratios had excellent physical characteristics, such as container capacity and total porosity, and the drainage EC level showed a high value of $3.0-6.8dS{\cdot}m^{-1}$. When the amount of irrigation is provided based on the drainage rate, the group provided the nutrient solution on the basis of 10% drainage supplied 91 L per plant, which was reduced by about 30% compared to the group with the highest water supply. In addition, the total drainage showed less than 10 L per plant with a minimum water supply and was reduced by 30 - 70% in substrate with a high dust rates. In substrate with high water supply and high dust ratio, leaf growth and fruit enlargement were good, and the soluble solids content varies greatly from cultivar to cultivar. If you provided the amount of irrigation based on 10% drainage rate, the fruit weight will be decreased, but the amount of irrigation can be reduced. Therefore, it is considered that managing the water & nutrient properly taking into account the characteristics of coir substrate and cultivar can produce melon of uniform quality using hydroponics.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.374-390
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• 2021

Growth and yield of field vegetable crops would be affected by climate conditions, which cause a relatively large fluctuation in crop production and consumer price over years. The yield prediction system for these crops would support decision-making on policies to manage supply and demands. The objectives of this study were to compile literatures related to onion and garlic and to perform data-mining analysis, which would shed lights on the development of crop models for these major field vegetable crops in Korea. The literatures on crop growth and yield were collected from the databases operated by Research Information Sharing Service, National Science & Technology Information Service and SCOPUS. The keywords were chosen to retrieve research outcomes related to crop growth and yield of onion and garlic. These literatures were analyzed using text mining approaches including word cloud and semantic networks. It was found that the number of publications was considerably less for the field vegetable crops compared with rice. Still, specific patterns between previous research outcomes were identified using the text mining methods. For example, climate change and remote sensing were major topics of interest for growth and yield of onion and garlic. The impact of temperature and irrigation on crop growth was also assessed in the previous studies. It was also found that yield of onion and garlic would be affected by both environment and crop management conditions including sowing time, variety, seed treatment method, irrigation interval, fertilization amount and fertilizer composition. For meteorological conditions, temperature, precipitation, solar radiation and humidity were found to be the major factors in the literatures. These indicate that crop models need to take into account both environmental and crop management practices for reliable prediction of crop yield.

• Journal of fish pathology
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• v.35 no.1
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• pp.1-25
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• 2022

The aquaculture industry has developed rapidly over the last three decades and is an important industry that supplies over 15% of humans' animal protein intake; therefore, there is a need to increase production to meet the continuous demand. The fish cage farms on the southern coast (Kyengsangnam-do and Jeollanam-do) of Korea are critical resources in aquaculture because they account for approximately 90% of the national total fish cage farms by water area ratio. However, the current aquaculture environment is being gradually affected by climate change, which is a global issue, and its effects are expected to intensify in the future. Therefore, it is urgently imperative to accurately evaluate the effects of climate change on South Korean aquaculture industries and to develop social and national strategies to minimize damage to the fishing industry. The damage to fish farmed in cage farms on the southern coast is increasing annually and the leading causes are high and low water temperature and red tides, which are directly or indirectly related to climate change. At present, global warming can provide opportunities for aquaculture industrialization of fish or other novel species, with economic implications. However, despite such opportunities, the influx of new species can also cause problems such as ecological disturbances, increase in the reproduction frequency of microalgae such as red tide, increase in disease incidence, and occurrence and periods of high water temperatures in summer. The scale of farmed fish mortality is increasing due to the complex effects of these factors. Increased damages due to fish mortality not only have severe economic impacts on the aquaculture industry, but the social costs of responding to the damage and follow-up measures also increase. various active responses can reduce the mortality damage in fish farms such as improving the management skills in aquaculture, improved species breeding, efficient food management, disease prevention, proactive responses, and system-wide improvements. This review article analyzes the large-scale mortality cases occurring in fish cage farms on the southern coast of Korea and proposes measures to mitigate mortality and enhance responses to such scenarios.

• The Journal of Natural Sciences
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• v.14 no.1
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• pp.83-121
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• 2004

This study was carried out to examine how solid the production foundation of rice in Chung-Nam Province is, and, if not, to probe alternative measures through the size of farms specializing in rice, of which direction would be a pivot of rice industry-oriented policy. The results obtained can be summarized as follows : 1. The amount of rice production in Chung-Nam Province is highest in Korea and the size of paddy field area is the second largest : This implying that the probability that rice production in Chung-Nam Province would be severely influenced by a global trend of market conditions. The number of farms specializing in rice becoming the core group of rice farming account for 7.7 percent of the total number of farm household in Korea. Average field area financial support which had been input to farm household by Government had a noticeable effect on the improvement of the policy of farm-size program. 2. Farm-size program in Chung-Nam Province established from 1980 to 2002 in creased the cultivation size of paddy field to 19,484 hectares, and this program enhanced the buying and selling of farmland and the number of farmland bargain reached 6,431 household and 16,517 hectares, respectively, in 1995-2002. Meanwhile, long-term letting and hiring of farmland appeared so active that the bargain acreage reached 6,970 hectares, and farm involved was 7,059 households, however, the farm-exchange-and-unity program did not satisfy our expectation, because the retirement farm operators reluctantly participated to sell their farms. Another reason that had delayed the bargain of farms rested on the general category of social complication attendant upon the exchange and unity operation for scattered farm. Such difficulties would work negative effects out to carry on the target of farm-size work in general. 3. The following measures were presented to propel the farm-size promotion program : a. Occupation shift project, followed by the social security program for retirement and elderly farm operators, should be promptly established and also a number of types of incentives for promoting the letting and hiring work and farm-exchange-and-unity program would also be set up. b. To establish the effective key system of rice production, all the farm operators should increase the unit area yield of rice and lower the production cost. To do so, a great deal of production teams of rice equipped with managerial techniques and capabilities need to be organized. And, also, there should be appropriate arrays of facilities including information system. This plan is desirable to be in line with a diversity of the structural implement of regional integration based on farm system building. c. To extend the size of farm and to improve farm management, we have to devise the enlargement of individual size of farm for maximized management and the utilization of farm-size grouping method. In conclusion, it can be said that the farm-size project in Chung-Nam Province which has continued since the 1980s was satisfactorily achieved. However, we still have a lot of problems to be solved to break down the barrier for attainment of the desirable farm-size operation work.. Farm-size project has fairly close relation with farm specialization in rice and, thus, the positive support for farm household including the integrated program for both retirement farmers and off-farm operators should be considered to pursue the progressive development of the farm-size program, which is key means to successful achievement of rice farming enforcement in Chung-Nam Province.

• Asia pacific journal of information systems
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• v.21 no.4
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• pp.45-62
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• 2011

The notion of information systems (IS) continuance has recently emerged as one of the most important research issues in the field of IS. A great deal of research has been conducted thus far on the basis of theories adapted from various disciplines including consumer behaviors and social psychology, in addition to theories regarding information technology (IT) acceptance. This previous body of knowledge provides a robust research framework that can already account for the determination of IS continuance; however, this research points to other, thus-far-unelucidated determinant factors such as habit, which were not included in traditional IT acceptance frameworks, and also re-emphasizes the importance of emotion-related constructs such as satisfaction in addition to conscious intention with rational beliefs such as usefulness. Experiences should also be considered one of the most important factors determining the characteristics of information system (IS) continuance and the features distinct from those determining IS acceptance, because more experienced users may have more opportunities for IS use, which would allow them more frequent use than would be available to less experienced or non-experienced users. Interestingly, experience has dual features that may contradictorily influence IS use. On one hand, attitudes predicated on direct experience have been shown to predict behavior better than attitudes from indirect experience or without experience; as more information is available, direct experience may render IS use a more salient behavior, and may also make IS use more accessible via memory. Therefore, experience may serve to intensify the relationship between IS use and conscious intention with evaluations, On the other hand, experience may culminate in the formation of habits: greater experience may also imply more frequent performance of the behavior, which may lead to the formation of habits, Hence, like experience, users' activation of an IS may be more dependent on habit-that is, unconscious automatic use without deliberation regarding the IS-and less dependent on conscious intentions, Furthermore, experiences can provide basic information necessary for satisfaction with the use of a specific IS, thus spurring the formation of both conscious intentions and unconscious habits, Whereas IT adoption Is a one-time decision, IS continuance may be a series of users' decisions and evaluations based on satisfaction with IS use. Moreover. habits also cannot be formed without satisfaction, even when a behavior is carried out repeatedly. Thus, experiences also play a critical role in satisfaction, as satisfaction is the consequence of direct experiences of actual behaviors. In particular, emotional experiences such as enjoyment can become as influential on IS use as are utilitarian experiences such as usefulness; this is especially true in light of the modern increase in membership-based hedonic systems - including online games, web-based social network services (SNS), blogs, and portals-all of which attempt to provide users with self-fulfilling value. Therefore, in order to understand more clearly the role of experiences in IS continuance, analysis must be conducted under a research framework that includes intentions, habits, and satisfaction, as experience may not only have duration-based moderating effects on the relationship between both intention and habit and the activation of IS use, but may also have content-based positive effects on satisfaction. This is consistent with the basic assumptions regarding the determining factors in IS continuance as suggested by Oritz de Guinea and Markus: consciousness, emotion, and habit. The principal objective of this study was to explore and assess the effects of experiences in IS continuance, with special consideration given to conscious intentions and unconscious habits, as well as satisfaction. IN service of this goal, along with a review of the relevant literature regarding the effects of experiences and habit on continuous IS use, this study suggested a research model that represents the roles of experience: its moderating role in the relationships of IS continuance with both conscious intention and unconscious habit, and its antecedent role in the development of satisfaction. For the validation of this research model. Korean university student users of 'Cyworld', one of the most influential social network services in South Korea, were surveyed, and the data were analyzed via partial least square (PLS) analysis to assess the implications of this study. In result most hypotheses in our research model were statistically supported with the exception of one. Although one hypothesis was not supported, the study's findings provide us with some important implications. First the role of experience in IS continuance differs from its role in IS acceptance. Second, the use of IS was explained by the dynamic balance between habit and intention. Third, the importance of satisfaction was confirmed from the perspective of IS continuance with experience.

• The Korean Society of Law and Medicine
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• v.24 no.3
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• pp.59-104
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• 2023

This essay attempts to analyze the public health welfare conception within the text of the Beveridge Report and its realization via the NHS in Great Britain. Once referring to the influence of the Report to create the foundations of the 20th-century welfare system, the quest to scrutinize the original intentions of the Report and its succession to the NHS is certainly intriguing. Furthermore, when regarding the significance of public health policy for a modern state, the effort to engage in Beveridge's conception and its realization is more than timely. In light of such a premise, this paper indulges in its study by the following methods. First, the historical background of the Report - namely, the role of the spirit of the age and the experience of the Emergency Medical Service are to be analyzed to identify the origins of the welfare policies proposed by Beveridge. Furthermore, the public health welfare conception of the Report conceived from its time is reflected upon by engaging on the goal towards social welfare and public health scheme. Lastly, the aims of the NHS and its management, treatment classification, and rehabilitation program are reviewed for comparative analysis with the Report to survey the realization of Beveridge's design. In this process, this paper not only takes into account the original text of the Report - but also other essential works of law and public policy, including the NHS Constitution for England and the National Health Service Act of 1946. The intentions of this study are not bound by merely coinciding with the Report, but resonate significance via reflecting upon the Beveridgian legacy on the modern welfare state from the current perspective. The structured analysis to research the aims and policies of the Report and to compare them to the reality of the NHS may provide an opportunity to confirm the realization of Beveridge's scheme in British society. In addition, this essay is part of an academic endeavor to critically assess the past and the present of the welfare institution in the public health sector. As such, it is hopeful that the essay sheds light on further studies concerning the constructive remedies of the Korean welfare system as well.