• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.481-490
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• 2016

Bluetooth utilizes a symmetric key that is exchanged at the first pairing to establish a secure channel. There are four authentication modes which enables device authentication, Just work, Passkey Entry, Out of Band, and Numeric Comparison. Up to now, Just work has been considered as the authentication mode that is vulnerable to Man-In-The-Middle (MITM) Attack. In addition, it is possible to intentionally change any authentication mode to Just work mode, in order to succeed in MITM Attack under Just work mode. However, this kind of attacks have just worked under the assumption that users should not notice that authentication mode was changed. In this paper, We analyze the specification of Secure Simple Pairing, LE Legacy Pairing and LE Secure Connection Pairing. When using Passkey Entry mode on each approach, it seems the MITM attack is possible. Also it offers Passkey Entry MITM attack that does not require assumptions about the user's fault, because it isn't change verification process of the authentication mode unlike traditional attacks. We implement the proposed MITM attacks. Also we presents a scenario in which an attack can be exploited and a countermeasure.

• Korean Journal of Social Welfare
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• v.52
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• pp.5-32
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• 2003

This paper examines the labor entry of conditional welfare recipients. This paper focuses on two questions. First, what is the percentage of conditional welfare recipients who have labor entry? Second, what are the predictors in the labor entry and the duration to the entry? Using Data about 917 welfare recipients who participated in the self-sufficiency programs of the Offices for Secure Employment in Seoul, this paper attempts to answer the above questions. Logistic regression analysis and survival analysis are adopted to identify variables predicting labor entry of conditional welfare recipients. This paper also utilizes a multiple imputation method to deal with the limitation of data by the missing values in some variables. The major findings are as follows: about 43.8% of the conditional welfare recipients have successful labor entry; and in the labor entry and the duration to the entry, gender, household, information and referral services for employment, health and willingness for self-sufficiency are the predictors that are statistically significant. Among these variables, health and willingness for self-sufficiency are more noticeable; it is recognized that programs to care for health of welfare recipients who want to have the labor entry and counseling programs to strengthen welfare recipients' willingness for labor entry are very important for them to be successful in the labor entry. This paper provides a basic knowledge about realities of the conditional welfare recipients' labor entry, identifies research areas for further research, and develops policy implications for their self-sufficiency.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.4
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• pp.30-37
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• 2007

In this paper, Water Entry Point Selection Algorithm(WEPSA) for selecting an optimal Water Entry Point of anti-submarine missiles which maximizes Detection Probability about a given target was investigated. WEPSA is a method which decides the position of an optimal Water Entry Point with calculating the target Detection Probability of a torpedo in the whole domain which centered by the target, performing the Monte-Carlo Simulations which include errors for the target informations and for weapon delivery. We can decide an optimal Water Entry Point of anti-submarine missiles which maximizes Detection Probability about a given target with WEPSA, if we get target informations about target range, target bearing, target speed and target course from Combat Systems.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.97-103
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• 2011

This study is numerical analysis on flow characteristic in a standard cyclone dust separator. The cyclone dust separator is widely used in a industrial applications as a method for dust removed from gases. In cyclone chamber, a very complex flow field is formed, involving the interaction between highly swirling velocity and turbulent field. Numerical analysis with computational fluid dynamics(CFD) was carried out to investigate the working fluid that flow into cyclone dust separator. Helical entry type was increasing flow rate compared with tangent entry type. And according to increasing pressure difference was increased fan power. But, helical entry type was high performance dust separator, in comparison with tangent entry type.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.115-123
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• 2004

A recursive tree is constructed by starting with a root node and repeatedly adjoining new nodes to one node of the tree already constructed. Such a tree can represent, for example, the heirarchy of a workforce of a company that grows via recruiting. At times of economic depression, the company may decide to layoff participants, and in some cases it is a fair policy to relieve the last senior worker (most recent entry in the tree). If we remove an edge from such a tree then it falls into two subtrees one of which contains the most recent entry. If we continue to remove edges from the successively smaller subtrees that contain the most recent entry, we eventually isolate the most recent entry. We consider how many randomly selected edges must be removed in average before isolating the most recent entry by this procedure.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.596-603
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• 1998

The entry compression wave, which is generated at the entrance of the tunnel, is almost always associated with the pressure transients in the tunnel as well as the impulse noise at the exit of the tunnel. It is highly required to design the train nose shape that can minimize such undesirable phenomena. The objective of the current work is to investigate the effects of the train nose shape on the entry compression wave. Numerical computations were applied to one-dimensional unsteady compressible flow in high-speed railway train/tunnel systems. A various shape of train noses were tested for a wide range of train speeds. The results showed that the strength of the entry compression wave is not influenced by the train nose shape, but the time variation of pressure in the entry compression wavefront is strongly related to the train nose shape. The current method of the characteristics was able to represent a desirable nose shape for various train speeds. Optimum nose shape was found to considerably reduce the maximum pressure gradient of the entry compression wave.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.145-146
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• 2019

SDN(Software Defined Networking) 환경에서는 OpenFlow 프로토콜을 사용함으로써, 컨트롤러는 스위치가 패킷의 도착이나 Table의 상태에 따라 미리 Flow table의 Entry를 추가, 갱신, 삭제하도록 제어한다. 본 논문에서는 Flow entry의 사용량에 대한 확률을 정확하게 측정하기 위하여 Hidden Markov Mode (HMM)을 적용한 새로운 Flow entry 사전 제거 기법을 제안한다. 본 연구를 통해 HMM을 사용하여 기존 기술들보다 효과적이며 Flow table 관리에 있어 향상된 성능을 목표로 한다.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.783-801
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• 2016

The purpose of this research is to grasp the influencing factors on the labor market entry of disabled women, and to suggest policy alternatives to support the labor market entry of them. This article utilized the survey data of the 3rd to the 7th Panel Survey of Employment for the Disabled in 2010-2014(by PSED), which is a longitudinal survey for the disabled in Korea. I analyzed the pattern changes of the labor market entry of them with the passage of years, and the influencing factors on that by the event history analysis. The major findings are as follows: First, according to the life table analysis involved in change of the labor market entry, 90% of them continued to remain the longest period of unemployment for four years and the labor market entry rate was only 10% of them. Second, the result of Cox regression analysis shows that public benefit recipient or not, the degree of disability and discrimination experience at the job market were factors to affect the labor market entry. With these results, this study suggested the practical alternatives to improve the labor market entry of disabled women.

• The Korean Journal of Pain
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• v.25 no.2
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• pp.81-88
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• 2012

Background: In discography performed during percutaneous endoscopic lumbar discectomy (PELD) via the posterolateral approach, it is difficult to create a fluoroscopic tunnel view because a long needle is required for discography and the guide-wire used for consecutive PELD interrupts rotation of fluoroscope. A stereotactic system was designed to facilitate the determination of the needle entry point, and the feasibility of this system was evaluated during interventional spine procedures. Methods: A newly designed stereotactic guidance system underwent a field test application for PELD. Sixty patients who underwent single-level PELD at L4-L5 were randomly divided into conventional or stereotactic groups. PELD was performed via the posterolateral approach using the entry point on the skin determined by premeasured distance from the midline and angles according to preoperative magnetic resonance imaging (MRI) findings. Needle entry accuracy provided by the two groups was determined by comparing the distance and angle measured by postoperative computed tomography with those measured by preoperative MRI. The duration and radiation exposure for determining the entry point were measured in the groups. Results: The new stereotactic guidance system and the conventional method provided similarly accurate entry points for discography and consecutive PELD. However, the new stereotactic guidance system lowered the duration and radiation exposure for determining the entry point. Conclusions: The new stereotactic guidance system under fluoroscopy provided a reliable needle entry point for discography and consecutive PELD. Furthermore, it reduced the duration and radiation exposure associated with determining needle entry.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.355-372
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• 2017

Objective: The aim of this study is to investigate the performance and usability of ten-finger text entry on Tablet PCs. Background: Generally a soft keyboard is used on Tablet PCs. However, the soft keyboard's performance is usually worse than physical keyboard's performance. In this study, we proposed a modified keyboard for tablet PCs to improve the performance of ten-finger text entry and evaluated the performance and subjective ratings of the keyboard. Method: The modified soft keyboard that is suggested in this study was compared with current Google and Samsung soft keyboards on Tablet PCs. Results: The three keyboards were not significantly different in terms of typing speed, error rate, and mental workload and showed bad performance. Also, the subjective ratings were not shown positively. Conclusion: Based on our results, ten-finger text entry using soft keyboards on Tablet PCs seems to be very difficult. However, we need to research the possibility continuously since ten-finger text entry can improve typing speed. Application: Our study can be a starting point of research that explores ten-finger text entry on Tablet PCs. The new soft keyboard design can be one of the soft keyboard alternatives. However, the key factors to improve the performance and usability of the soft keyboard will not be 'key size' or 'convenience to typing special characters or numbers', but other factors (e.g., 'tactile feedback').