• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.129-134
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• 2013

The airport processes are restricted by some limits of performance objects as size of airport, ability of human resources, capacity of facilities and operational rules. These limitations make passenger handling difficult when passenger numbers increase. In order to solve this problem, we modeled the airport process and analyzed departure passenger arrival, scheduled security manpower under specific customer service level maintenance with mixed integer programming and validate the efficiency with simulation with adapting smart airport framework. We concluded that the airport management with information techniques can reduce waiting time within security and immigration process.

• Korean Journal of Mathematics
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• v.16 no.3
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• pp.323-334
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• 2008

We define injective and projective representations of quivers with two vertices with n arrows. In the representation of quivers we denote n edges between two vertices as ${\Rightarrow}$ and n maps as $f_1{\sim}f_n$, and $E{\oplus}E{\oplus}{\cdots}{\oplus}E$ (n times) as ${\oplus}_nE$. We show that if E is an injective left R-module, then $${\oplus}_nE{\Longrightarrow[50]^{p_1{\sim}p_n}}E$$ is an injective representation of $Q={\bullet}{\Rightarrow}{\bullet}$ where $p_i(a_1,a_2,{\cdots},a_n)=a_i,\;i{\in}\{1,2,{\cdots},n\}$. Dually we show that if $M_1{\Longrightarrow[50]^{f_1{\sim}f_n}}M_2$ is an injective representation of a quiver $Q={\bullet}{\Rightarrow}{\bullet}$ then $M_1$ and $M_2$ are injective left R-modules. We also show that if P is a projective left R-module, then $$P\Longrightarrow[50]^{i_1{\sim}i_n}{\oplus}_nP$$ is a projective representation of $Q={\bullet}{\Rightarrow}{\bullet}$ where $i_k$ is the kth injection. And if $M_1\Longrightarrow[50]^{f_1{\sim}f_n}M_2$ is an projective representation of a quiver $Q={\bullet}{\Rightarrow}{\bullet}$ then $M_1$ and $M_2$ are projective left R-modules.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.38-39
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• 2014

In order to reduce fatal accidents, a systematic safety management should be performed at a construction site. A lot of researches on direct causes of fatal accidents and indirect causes which affect the direct causes have been conducted for effective safety management. In the previous studies, these causes are considered separately because of the difficulty of recognition of indirect causes. It is also hard to measure the negative impact of these causes and notice their occurrence the perception of its problem. However, a study on identification of complicated relationship between these two types of causes is necessary since an accident occurs due to the chain reaction that indirect causes trigger the direct causes which lead to the fatal accidents. Therefore, this study proposes a safety management plan that considers indirect and direct causes of fatal accidents cases in the Korean construction industry. Then this paper suggests a plan of safety management by identifying major causes of the accidents.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.44-45
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• 2014

Recently the Korean government also has strictly restricted a law such as GBCC(Green Building Certification Criteria)and RPS(Renewable Portfolio Standard) on the construction. Especially the government announced a obligation of renewable energy consumption over 12% for all the public buildings of total area over 1,000㎡ since 2014. Regarding to the policy, this study presented the economics of energy analysis of the public office buildings that supplies 12% renewable energy output in the early stage of construction project. This paper calculated on CO₂ emission by the geothermal, solar heat, and solar photovoltaic system and estimated the saving cost. Reduced cost through the energy saving are predicted to influence on the total construction cost. As a result air pollution and energy saving cost are expected that renewable energy system would be saving total initial cost of construction on planning phase.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.754-755
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• 2015

Computer Vision Syndrome(CVS) is a temporary condition resulting from focusing the eyes on a computer display for protracted, uninterrupted periods of time. To prevent CVS, you have to blink your eyes frequently, also have to keep distances from monitor. In this paper, real-time notification system for preventing CVS by checking user's distance between eyes and monitor and user's frequency of nictation in real time through monitor webcam is described.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.259-263
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• 2015

The vulnerabilities related to Flash player which is widely used in internet browsers and office programs are gradually increased. To detect Flash malwares, previous work focuses on predefined features of ActionScript. However above work cannot detect new/mutated Flash malwares, since predefined features could not cover the new patterns of new/mutated Flash mawares. To solve this problem, we propose a Flash malware detection method that uses machine learning to learn Flash Tag patterns and classify Flash by using machine learning.

• Asia pacific journal of information systems
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• v.25 no.2
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• pp.265-288
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• 2015

IT convergence services, as the main stream of the digital age, are currently on their way to include the concept of Software as a Service (SaaS), where IT products and services are integrated as one. In particular, the recently introduced web-service-based SaaS is expected to be a more developed SaaS model. This new model provides greater influence on clients' job performances than its previous models, such as application service providers and the web-native phase. However, the effects of technology maturity on task performance have been overlooked in adoption and performance studies. Accordingly, this study introduces SaaS technology maturity as the exogenous technological characteristic influencing job performance. This study also examines the relationships among various SaaS-related performances according to the different levels of SaaS maturity. Results suggest that applying innovative technologies (such as SaaS), particularly when the technology reaches a certain level of maturity, is more helpful for managers in improving task-technology fit and job performance. This study makes an academic contribution by establishing and validating a performance model empirically with SaaS technology maturity perspectives.

• The Journal of the Acoustical Society of Korea
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• v.24 no.6
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• pp.358-364
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• 2005

In this Paper. we present a bitrate scalable speech codec which uses an ITU-T G.723.1 as the baseline coder and encodes the synthesis error signal in an enhancement coder. ITU-T P.862 (PESQ) is used to evaluate the Performance of the bitrate scalable coder. Experiments show that 6.7kbps enhancement layer based on G.723.1 5.3kbps produces the increase of 0.39 in MOS and 5.7kbps enhancement layer based on G.723.1 6.3kbps Produces the increase of 0.267 in MOS.

• East Asian mathematical journal
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• v.34 no.3
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• pp.305-316
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• 2018

Let R be a ring with identity. A right ideal ideal I of a ring R is called ref lexive (resp. completely ref lexive) if $aRb{\subseteq}I$ implies that $bRa{\subseteq}I$ (resp. if $ab{\subseteq}I$ implies that $ba{\subseteq}I$) for any $a,\;b{\in}R$. R is called ref lexive (resp. completely ref lexive) if the zero ideal of R is a reflexive ideal (resp. a completely reflexive ideal). Let K(R) (called the ref lexive radical of R) be the intersection of all reflexive ideals of R. In this paper, the following are investigated: (1) Some equivalent conditions on an reflexive ideal of a ring are obtained; (2) reflexive (resp. completely reflexive) property is Morita invariant; (3) For any ring R, we have $K(M_n(R))=M_n(K(R))$ where $M_n(R)$ is the ring of all n by n matrices over R; (4) For a ring R, we have $K(R)[x]{\subseteq}K(R[x])$; in particular, if R is quasi-Armendaritz, then R is reflexive if and only if R[x] is reflexive.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.1
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• pp.72-82
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• 2017

Sharing economy is expected to grow high with the notable development of Internet technology. Despite this importance, however, existing studies so far have addressed the consumers for the services of sharing economy in limited perspectives and have not properly considered the recent advent of technology. Especially, car sharing service is one of the cases that have been changed rapidly with growth of the Internet technology. In this sense, the present study focuses on car sharing service and analyzes the effects of its service factors on consumers' attitude and intention to use. In addition, we examine differences in such effects between two types of services, business to customer (B2C) and customer to customer (C2C). Based on the analysis results, we discuss the guidelines for successful development of services in sharing economy.