• Journal of the Korea Society for Simulation
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• v.28 no.4
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• pp.67-74
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• 2019

As the market for Internet of Things (IoT) service grows, the security issue of the data from IoT devices becomes more important. In this paper, we implemented a cryptographic library for confidentiality of sensor data from Android Things based IoT services. The library made use of the SEED algorithm for encryption/decryption of data and we verified the library by implementing a service environment. With the library, the data is securely encrypted and stored in the database and the service environment is able to represent the current sensing status with the decrypted sensor data. The contribution of this work is in verifying the usability of SEED based encryption library by implementation in IoT sensor based service environment.

• Journal of Korea Technology Innovation Society
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• v.17 no.4
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• pp.629-650
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• 2014

This paper aims at exploring the comparative impact of social networks and firm's absorptive capacity on the process of technological alliance such as technological alliance partner selection, governance structure and performance. Firms not only need to develop internal absorptive capacity but also need to cooperate with outside innovating entities. Increasing networks with other firms and enhancing firm's internal absorptive capacity become more and more important to enter into new market, increase network effects and develop firm's core capacities. In the view of firm's motivation for technological alliance such as expanding social networks and enhancing absorptive capacity, we develop hypotheses and tested comparative impact of those two constructs using 215 survey data of Korean venture companies. The results showed that absorptive capacity showed more impacts on the technological partner selection criteria than social networks. No impact was found between social network and alliance performance. Only absorptive capacity showed positive impact on the technological alliance success. Both constructs showed no impact on the choice of governance structure. In the conclusion section, we discussed the findings and implications of this study and directions for future studies.

• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.403-413
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• 2015

Social media has recently become one of the primary tools for viral marketing as an effective advertising channel, in order to maximize effects of world-of-mouth through social media, it is very important to obtain customer experience-centric differentiated contents in offline. However, viral marketing is still being implemented mainly based on online channels because of the lack of effective services and methods to support social medial marketing in conjunction with offline. On that account, this study proposes O2O(Online to Offline) based social media marketing method allowing customers to connect their personal experience conveniently and easily in offline in which they voluntarily participate. Furthermore, this study aims to verify the effectiveness of the proposed method by analyzing the empirical cases thereof. This study would eventually contribute to the vitalization of social media marketing market by enabling customers to obtain personalized posts as connecting online to offline organically and also by allowing corporations to get an ample amount of useful CRM information for planning marketing strategies.

• Journal of the Korean Data and Information Science Society
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• v.26 no.4
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• pp.791-799
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• 2015

In random walk hypothesis, we assume that current change of financial time series is independent of past values. It is interpreted as an existency of a unit root in ARMA models and many researches have been focused on whether ${\rho}$ < 1 or not. If some financial data are generated from an explosive autoregressive model, the chance of a bubble economy increases. We have to find the symptoms of it in advance. Since some well-known parameter estimators contain the parameter itself and other statistic is constructed under a specific parameter structure assumption, those are difficut to be adopted. In this paper we investigate a test for explosive autoregressive models using slope signs. We found the properties of the slope sign test statistic under both independent error and correlated error conditions, mainly by simulations.

• International Commerce and Information Review
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• v.17 no.2
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• pp.3-18
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• 2015

This thesis examines the performance and improvement strategy of SWIFTNet TSU's BPO for computerization and suggests the following results: First, the URBPO should be legally complemented, and the SWIFT and banks need to keep improving the systems to meet trade parties' diverse needs. Second, the SWIFTNet TSU's BPO should have an institutionally unified sharing platform with security, stability and convenience. In other words, it is needed to develop services which meet e-payment paradigm and international and regional environments through continued analysis on market changes and flow. Third, in order for the SWIFTNet TSU BPO to evolve into a perfect global system, there should be an innovative payment solution which can meet all trade parties all over the world. For this, technology standardization for a worldwide e-trade payment system is essential. Lastly, based on the results derived from this study, an analysis framework with which more diverse and practical environmental variables can be analyzed should be developed.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.32-37
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• 2018

Recently, the distributed power generation market using natural gas is expected to expand gradually according to the government's future energy conversion policy. Distributed power generation means small power generation source near the power demand site, which has the advantage of reducing the construction costs of the transmission and distribution infrastructure, operating cost and power loss. A typical example of distributed generation using natural gas is the trigeneration system. In this study, we conducted a basic study on the performance analysis of trigeneration desiccant system for dehumidifying / cooling / heating in the air conditioner room by using the cold and engine waste heat energy generated in the trigeneration system. It shows that the system efficiency increases and the energy consumption decreases as the temperature difference between the inlet and outlet of the trigeneration system increases compared with the general air conditioning system.

• Environmental and Resource Economics Review
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• v.24 no.2
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• pp.435-461
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• 2015

Recently, Korean development Institute includes water for environmental improvement as an additional water demand category in water resources development project. In response to this change, this paper is to measure benefits of providing additional water in Yeondok Ohsip River by applying contingent valuation method. This study extended the conventional CVM design by incorporating distance variable into WTP function of dichotonomous choice responses and treated protest bids by estimating sample-selection models. The empirical analysis exhibited that more than 30% of respondents were categorized as protest bids and the mean of WTP from sample selection models were three times higher than that of the whole sample. In addition, the distance variable had significantly negative impact on sample WTP regardless of variables forms, and the geographical market area were more 400km, which implies that beneficiaries of water service would the households from the whole nation.

• KDI Journal of Economic Policy
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• v.15 no.3
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• pp.131-160
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• 1993

본고(本稿)에서는 다양한 형태의 금융충격(金融衝擊)의 거시경제효과(巨視經濟效果)를 분석하기 위해, 모든 금융충격(金融衝擊)을 통화의 지불수단으로서의 이용률(利用率)을 급격하게 변화시킴으로써 화폐시장(貨幣市場)에 초과수요나 초과공급을 초래하는 현상으로 이해하고, 동 충격을 유통속도충격(流通速度衝擊)과 통화승수충격(通貨乘數衝擊)으로 분리하여 그 규모를 추정할 수 있도록 전자(前者)는 은행의 예금회전율(預金回轉率)과 현금통화보유성향(現金通貨保有性向)에 의해, 후자(後者)는 현금통화보유성향과 지급준비보유성향에 의해 설명하는 일반적인 모형을 개발했다. 동 모형을 아용하여 80년대 이후 우리나라의 금융충격사례(金融衝擊事例)에 대해 분석한 결과는 다음과 같다. 82년 거액어음사기사건과 7.3조치에 의한 실명제예고조치(實名制豫告措置)는 M2를 3% 이상 감소시키는 효과를 초래하였으나, 실제로는 통화당국의 대응으로 오히려 3.0% 수준의 M2가 초과공급된 반면, 1988년의 금융실명제(金融實名制) 실시예고와 민간(民間)에 의한 1993년 8월 12일의 금융실명제실시예견은 M2를 각각 3.9% 및 4.9% 감소시키는 효과를 초래하여 정부의 통화공급대응(通貨供給對應)에도 불구하고 결과적으로는 각각 0.8% 및 0.6% 수준의 M2 과소공급을 초래한 것으로 추정되었다. 93년 8월 12일의 금융실명제 전격실시는 개략적으로 7~8%의 M2 통화량감소효과를 초래한 것으로 추정되지만, 실제로는 통화당국(通貨當局)의 신축적 통화공급으로 0.3~0.6% 정도의 M2 초과공급이 이루어진 것으로 추정되었다. 한편 본고(本稿)에서는 이와 같이 추정된 사례별 금융충격의 거시경제효과(巨視經濟效果) 시뮬레이션 결과(結果)도 같이 보여주고 있다.

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.1049-1060
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• 2009

The expansion of volatility in Korean Stock Market made it more difficult for the individual to invest directly and increased the weight of indirect investment through a fund. The purpose of this study is to construct the EIF(enhanced index fund) model achieves an excessive return among several types of fund. For this purpose, this paper propose portfolio optimization model to manage an index fund by using GA(genetic algorithm), and apply the trading amount and the closing price of standard index to earn an excessive return add to index fund return. The result of the empirical analysis of this study suggested that the proposed model is well represented the trend of KOSPI 200 and the new investment strategies using this can make higher returns than Buy-and-Hold strategy by an index fund, if an appropriate number of stocks included.

• Journal of the Economic Geographical Society of Korea
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• v.19 no.1
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• pp.143-160
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• 2016

The official development assistance (ODA) accompanies an interstate financial transaction, such as trade, foreign direct investment, and money transfer. ODA policy has designated several purposes. Among them, political purposes have been considered to be the key factors in the regional distribution of foreign aid. If we agree the traditional approach that recognizes ODA as a 'political one', the practice of ODA can be a kind of state geopolitics. This study investigates the construction and characteristics of geopolitical discourses. More specifically, this study pays special attention to the 'practical geopolitics' that is crucial to the policy-making. By analyzing the minutes of the National Assembly Standing Committee, four geopolitical discourses were identified: 'practicing humanities as a developed country', 'providing a role model to developing countries', 'developing new foreign markets' and 'coping with global geopolitics'. These geopolitical discourses have been constructed through the process of justifying the ODA policy to the domestic and international audiences. Constructing discourses on ODA shows the representation of a dichotomous and typical image of developed/developing.