• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.12
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• pp.3798-3814
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• 2022

Social recommendation algorithm can alleviate data sparsity and cold start problems in recommendation system by integrated social information. Among them, matrix-based decomposition algorithms are the most widely used and studied. Such algorithms use dot product operations to calculate the similarity between users and items, which ignores user's potential preferences, reduces algorithms' recommendation accuracy. This deficiency can be avoided by a metric learning-based social recommendation algorithm, which learns the distance between user embedding vectors and item embedding vectors instead of vector dot-product operations. However, previous works provide no theoretical explanation for its plausibility. Moreover, most works focus on the indirect impact of social friends on user's preferences, ignoring the direct impact on user's rating preferences, which is the influence of user rating preferences. To solve these problems, this study proposes a user bias drift social recommendation algorithm based on metric learning (BDML). The main work of this paper is as follows: (1) the process of introducing metric learning in the social recommendation scenario is introduced in the form of equations, and explained the reason why metric learning can replace the click operation; (2) a new user bias is constructed to simultaneously model the impact of social relationships on user's ratings preferences and user's preferences; Experimental results on two datasets show that the BDML algorithm proposed in this study has better recommendation accuracy compared with other comparison algorithms, and will be able to guarantee the recommendation effect in a more sparse dataset.

• International Journal of Contents
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• v.8 no.1
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• pp.47-54
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• 2012

The dynamic adaptation between various service environments using the application profiles for the service continuity is a key issue of the profile-based service continuity framework (PSCF) for N-screen service using next generation networks. PSCF offers an optimized service framework for providing continuous user services, which are multimedia video streaming, educational broadcasting, game, etc., using the various devices that are not restricted by the service environment of the user. This paper specifies the functional model of PSCF, service scenario and explains the experimental results of the service continuity for N-screen service using PSCF.

• Journal of Information Technology Services
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• v.11 no.sup
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• pp.165-176
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• 2012

Context-Awareness system provides an appropriate service to user by recognizing situation from surrounding environment. There are many successful studies on this framework, but still has some limitations. In this paper, we are describing a context-awareness middleware that can enhance the limitation of the previous approaches. We first defined a new concept of context-awareness environment as a social intelligence. This concept implies that intelligent objects can make relationships, can aware of situation from surrounding environment, and can collaborate to accomplish a given task. The significance of the study is as follows. First, the system is capable of multi context-awareness since it is designed with a structure that supports multiple lines of reasoning. Second, the system is capable of context planning by adapting AI planning mechanism. Third, the system is capable of making the intelligent objects as a group for collaboration, and provides adaptive service to user. We have developed a prototype of the system and tested with a virtual scenario.

• Journal of Korea Trade
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• v.25 no.3
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• pp.1-20
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• 2021

Purpose - The purpose of this paper is to examine the welfare effects of standards harmonization between technologically asymmetric countries, and to determine optimal harmonization strategies for a country with mid-level technological advancement. Design/methodology - Following Salop's circular city model (Salop, 1979), this study constructs a simple, horizontally-differentiated oligopoly model in which three firms and three countries exist. Each country adopts different compatibility standards and each firm incurs conversion costs for foreign market access due to differences in standards. The conversion costs are related to technology; standards harmonization removes these costs between participating countries. The paper considers three cases: i) no harmonization; ii) harmonization with the more technologically-advanced country and iii) harmonization with the less technologically-advanced country. Findings - The paper first considers a scenario in which all three firms occupy some share of the market in each country. It shows that standards harmonization with both the technologically moreor less-advanced country always increases consumer surplus and social welfare. In addition, the producer surplus will increase if the harmonization partner has a higher technology level, whereas it may decrease if the partner has a lower technology level. It also shows that if most domestic export goods are in sectors with conversion costs above a certain level, harmonizing standards with a technologically more-advanced country should be prioritized. Such strategies, moreover, should be emphasized when there exists a large technology gap among countries. Lastly, the paper considers another scenario, in which harmonization leads to the foreclosure of the non-member firm from the member countries' markets. It shows that harmonization improves the social welfare of a mid-level technology country regardless of its partner's technology. It also shows that the country should prioritize harmonization with the technologically less-advanced country. Originality/value - Though some of the existing studies consider the welfare effects of harmonization, their main assumption is that firms have the same conversion technology. Since complying with standards often requires substantial technological advancement and technical expertise, harmonization of compatibility standards between countries with gaps in technological ability carries different implications. This paper investigates the welfare effects of this harmonization and determines an optimal harmonization strategy while considering technological asymmetry among countries in standards compliance.

• International Journal of High-Rise Buildings
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• v.12 no.2
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• pp.179-193
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• 2023

It is undeniable that urban greenspace is the soul of a city. Conventional urban greenspace such as parks, community gardens, playgrounds etc. located within a city reduce the negative effects of pollution, play a major role in the survival of the urban ecosystem, and promote healthy lifestyles. Today, 55% of the world's population lives in urban areas, which is expected to increase to 68% by 2050. Projections show that urbanization and the gradual migration to urban areas combined with the fast growth of the world's population, could add another 2.5 billion people to urban areas by 2050 and almost 90% of this increase will take place in Asia(UN, 2018). As a result, many plots in the cities are and will continue to be occupied with buildings to provide residential support to the increased population. This will dangerously decrease urban greenspaces. Moreover, worldwide, food crisis, energy crisis, and social crisis is posing a great threat to the existence of mankind. Additionally, the COVID - 19 has introduced a new lifestyle where from work culture to community configuration has drastically transformed. In this scenario, residential buildings will have to serve more than just providing privacy and shelter. As urban greenspaces are being occupied by concrete residential buildings, these buildings will have to compensate for the percentage of urban green they are destroying and the issues they are imposing in the process. The goal of this thesis is to design, architecturally define and, categorize comprehensive 'sustainable Greenspace'(S.G.S) for the multi-family housing scenario. These will be different than the conventional green (veranda, rooftop green) we commonly see in residential buildings. An old, dilapidated apartment building will be the target of remodeling to fulfill the purpose of this thesis.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1595-1606
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• 2018

Recently, there has been an increase in the number of social engineering techniques that indirectly attack the target system administrators or organizational weaknesses rather than the traditional technical cyber attacks that directly attacked the target systems. Accordingly, the type analysis and case study of social engineering techniques are being actively conducted. There has been, however, little effort to derive an analysis model that systematically analyzes social engineering based cyberspace operations. Therefore, this paper aims at building a Social Engineering Based Cyberspace Operations Analysis Model, which can be used as a reference framework for a case study or attack scenario generation of social engineering based cyberspace operations.

• Journal of Practical Engineering Education
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• v.10 no.1
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• pp.73-79
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• 2018

The purpose of this study is to explore the supporting scenario to promote vocational training in North Korea in terms of cooperation level. To this end, we have embarked on a regional and industry based vocational training program by predicting the political and social situation of North Korea and staging three scenarios systematically. These scenarios were designed originally based on the Futures Group methodology. The first scenario is to establish a technical training center in one area, focusing on the electrical, electronics, and clothing sectors. The second scenario is to set up a pilot campus of vocational training college in one region by selecting the electric, electronic, and automobile industries as its main industries. The third scenario is to establish five vocational training college campuses in North Korea, focusing on electricity and electronics, IT manufacturing, telecommunications, heavy industry, and women-specialized industries. We suggested the followings: First, establishing goals and strategies for North Korean vocational training and establishing road maps. Second, the North Korean vocational training governance system needs to be established. Third, R & D infrastructure for vocational training needs to be established. Fourth, HRD and HRM system in North Korea vocational training field needs to be established. In addition, the role of public and private employment services centers to provide them should be strengthening.

• 한국노년학
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• v.31 no.4
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• pp.1047-1065
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• 2011

The main purpose of this study is to provide the sustainability and continuous development of Long-term care Insurance in projecting changes of the Long-term care Insurance beneficiary population and Cost. We conducted a transformed cohort-component projection method that are employed for the beneficiary population projection and applied the previous experiences in Japan and German. A transformed cohort-component method means that we also projected the increasing beneficiary of long-term care insurance for using the data of geriatric disease in NHIC and estimated the cost of insurance's financial resources. First of all, beneficiary increase and strategy of extending to level 4 are categorized 2 and the expense account projection are categorized 2. If it is thought experience of Japan and German, The Level 4 extend of insuree is projected 2012 or 2013. With the results of this study, we proposed that extended level 4 insuree include the 40%~90% of geriatric disease in elderly people. The number of beneficiaries in 2011 is expected to reach to about 342,896 and in 2015 is 415,905 on scenario 1. Scenario 2(40%of geriatric disease in elderly people), the number of beneficiaries in 2011 is 342,896 and in 2015 is 483,453. Scenario 3(90%of geriatric disease in elderly people), the number of beneficiaries in 2012 is 545,068 and in 2015 is 565,565. The cost of beneficiaries insurance benefit of scenario 1 are projected from 3,000billion in 2012 to 3,500billion won in 2015. Scenario 2 are projected from 3,100billion in 2012 to 4,000billion won 2015. Finally, The cost of Level 4 extending are need minimum 300billion to maximum 1,400billion won.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.761-767
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• 2011

Since the "Low Carbon, Green Growth" as a social requirements is attracted public attention, the policies and investments of the railway which have been less estimated than road is re-considered. Since the starting the commercial service (2004. April), the KTX have been operated successfully while transport passengers over 100million for years. And also the project for development of KHST (Korea High Speed Train ; G7) had been accomplished with a good result, the first trainset of KTX-II which base on G7 project was manufactured and testing now. On the other hand, the world's technology of the high speed train is more faster, and changing to a distributed traction system. To catch up the world's leading technology, the HEMU(High-speed Electric Multiple Unit) project will secure new technology and aims to promote the technology of domestic high-speed train. The authors indicates the result of detail review such as a curve, slope of the track and electrical dead section of the catenary to test at 400kph and also the performance simulation of the developed rolling stock in this paper. As the result, the authors devise the test scenario to perform a maximum speed test (stability at max. speed, acceleration & deceleration etc) with the restricted conditions such as track length, track available time etc by considering above result.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.71-79
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• 2014

Climate change has been social and environmental issues, it typically indicates the trend changes of not only temperature but also rainfall. There is a need to consider climate changes in a long-term soil erosion estimation since soil loss in a watershed can be varied by the changes of rainfall intensity and frequency of torrential rainfall. The impacts of rainfall trend changes on soil loss, one of climate changes, were estimated using Sediment Assessment Tool for Effective Erosion Control (SATEEC) employing L module with current climate scenario and future climate scenario collected from the Korea Meteorological Administration. A 62 $km^2$ watershed was selected to explore the climate changes on soil loss. SATEEC provided an increasing trend of soil loss with the climate change scenarios, which were 182 ton/ha/year in 2010s, 169 ton/ha/year in 2020s, 192 ton/ha/year in 2030s,182 ton/ha/year in 2040s, and 218 ton/ha/year in 2050s. Moreover, it was found that approximately 90% of agricultural area in the watershed displayed the soil loss of 50 ton/ha/year which is exceeding the allow able soil loss regulation by the Ministry of Environment.