• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1236-1245
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• 2000

This paper propose a novel scheme, called Mobiel Terminal Initiated Scheme(MTIS), in which mobile terminal initiates the backward handover by sending handover request message with the list of target radio ports. In this scheme, the old ATM switch suporting end-user mobility, denoted by EMAS\ulcorner, checks whether each EMAS\ulcorner, managing the target radio port, has its available resources. If it has, the EMAS\ulcorner performs the path rerouting between CrossOver Switch (COS) and itself after deciding the most suitable target radio port. Therefore, the MT initiates the handover after deciding the most suitable target radio port through the beacon signal of Wireless Access Point (WAP). The EMAS\ulcorner have only to check the resource availability of the target radio port. It is no need to waste time to decide the suitable target radio port. Also, once receiving the request of the resource availability, the EMAS\ulcorner can reduce the rerouting delay time due to perform the path rerouting to the COS. In comparison with that of the ATM-Forum procedure, our proposed MTIS handover delay time reduced 14~21%, and end-to-end transfer delay time reduced 2~9%, as a result of the simulation.

• Journal of KIISE
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• v.44 no.4
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• pp.352-362
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• 2017

This paper analyzes security threats in Security Enhanced (SE) Android and proposes a new technique to efficiently protect application data including private information on rooted Android phones. On an unrooted device, application data can be accessed by the application itself according to the access control models. However, on a rooted device, a root-privileged shell can disable part or all of the access control model enforcement procedures. Therefore, a root-privileged shell can directly access sensitive data of other applications, and a malicious application can leak the data of other applications outside the device. To address this problem, the proposed technique allows only some specific processes to access to the data of other applications including private information by modifying the existing SEAndroid Linux Security Module (LSM) Hook function. Also, a new domain type of process is added to the target system to enforce stronger security rules. In addition, the proposed technique separates the directory type of a newly installed application and the directory type of previously installed applications. Experimental results show that the proposed technique can effectively protect the data of each application and incur performance overhead up to or less than 2 seconds.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.780-788
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• 2011

This paper suggests one model, which can be monitor and control target system at anytime and anywhere by a WAP and ME based personal cellular phone(Feature phone) and internet connection. The suggesting model tried to overcome constraints of distance and mobility of conventional methods, TCP/IP based remote data monitoring system, which combine PDA and WLAN technologies. For the experiments of suggesting model, the target systems are constructed with individual modules, which need AC or DC power control. The development software for the control and monitor of local system use NI Labview for the easy-programming and confidence. Also, web server use APM setup for the general user. The mobile connection environments of personal cellular phone are programmed by use WML and mHTML language for the general access. Through the experiments, we have showed that suggesting model can overcome constraints of distance and mobility of conventional system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.1
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• pp.115-126
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• 1996

In the time optimal control problem, bang-bang control has been used becaese it is the theoretical time minimum solution. However, to improve tracking speed performance in the time optimal control, it is important to select a switching point accurately which makes the velocity zero near the target track. But it is not easy to select the swiching point accurately because of the damping coefficient variation and uncertainties of modeling an actual system. The Adaptive model following control(AMFC) is implemented to relieve the difficulty and inconvenience of this task. The AMFC and make the controlled plant follow as closely as possible to a desired reference model whose switching point can be calculated easily and accurately, assuring the error between the states of the reference model and those of the controlled plant appoaches zero. The hybrid control method composed of AMFC and PID is applied to a tracking actuator of the magneto optical disk drive(MODD) in random access devices to improve its slow tracking performance. According to the simulaion and experimental results, the average tracking time as small as 20ms is obtained for a 3.5 magneto-optical disk drive. The AMFC also can be applied for other random access devices to improve the average tracking performance.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.683-687
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• 2009

Track jump control is a random access strategy for short distance movement. The most common track jump scheme is a bang-bang control of a kick and brake manner. In a conventional track jump scheme, a track-following compensator is turned off during kick and brake periods, and restarted at a target track for track pull-in. The inevitable controller switching with non-zero initial condition results in undesirable transient response, and excessive overshoot in the transient response causes track pull-in failure. In this paper, a new track jump scheme is proposed for enhancing track jump stability. Instead of control switching, internal states of a track-following controller are artificially manipulated for kick and brake actions in a digital control environment. Experimental results are provided in comparison with conventional track jumps.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.6
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• pp.1355-1362
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• 2012

As the utilization of cloud computing service rapidly increases to meet demands for various forms of service recently, the virtualization technology has made a rapid rise, further leading to some issues related to security, such as safety and reliability. As a system to provide environments what multiple virtual operating systems can be loaded, hypervisors may be a target of various attacks, such as control loss and authority seizure, since all the agents fcan be damaged by a malicious access to the virtualization layer. Therefore, this paper was conducted to investigate the access control for agents and suggest a plan to control malicious accesses to the cloud virtualization internal environment. The suggested technique was verified not to have effect on the performance of the system and environment through an analysis of its performance.

• Journal of Information Technology Services
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• v.19 no.5
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• pp.33-47
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• 2020

In recent years, due to the demand for operating efficiency and cost reduction of industrial facilities, remote access via the Internet is expanding. the control network accelerates from network separation to network connection due to the development of IIoT (Industrial Internet of Things) technology. Transition of control network is a new opportunity, but concerns about cybersecurity are also growing. Therefore, manufacturers must reflect security compliance and standards in consideration of the Internet connection environment, and enterprises must newly recognize the connection area of the control network as a security management target. In this study, the core target of the control system security threat is defined as the network boundary, and issues regarding the security architecture configuration for the boundary and the role & responsibility of the working organization are covered. Enterprises do not integrate the design organization with the operation organization after go-live, and are not consistently reflecting security considerations from design to operation. At this point, the expansion of the control network is a big transition that calls for the establishment of a responsible organization and reinforcement of the role of the network boundary area where there is a concern about lack of management. Thus, through the organization of the facility network and the analysis of the roles between each organization, an static perspective and difference in perception were derived. In addition, standards and guidelines required for reinforcing network boundary security were studied to address essential operational standards that required the Internet connection of the control network. This study will help establish a network boundary management system that should be considered at the enterprise level in the future.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.93-102
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• 2010

Existing web based information service system solutions show limitations in mobile information services, as well as problems such as uncertain error messages, and difficulty providing swift assistance or real time emergency support. In order to solve these deficiencies, a realtime wireless remote control system has been designed and implemented in this thesis, which is capable of managing and monitoring remote systems using mobile communication devices (Mobile Phone, PDA, Smart Phone) for realtime control. Proposed systems are applied at remote places, for instance 'office building', and a nursery school like 'kindergarten'. In the case of implemented at office building, it can be managing and controlling at real time all sorts of the sensor information that are installed at office building system environment through wire(web environment) or wireless(mobile device). In the other case at kindergarten system that are providing the real-time wireless remote control and monitoring system can be monitoring activity of kindergarten children with a mobile phone of authentication user. The security functions of proposed systems include mobile device user authentication and target system access control. The proposed systems allow real-time user authentication function and system access control function that improve the security of resource administrators and mobile device users, and provides not only uninterrupted services, but also real time mobile service environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4662-4679
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• 2015

Currently, the leakage of internal information has emerged as one of the most significant security concerns in enterprise computing environments. Especially, damage due to internal information leakage by insiders is more serious than that by outsiders because insiders have considerable knowledge of the system's identification and password (ID&P/W), the security system, and the main location of sensitive data. Therefore, many security companies are developing internal data leakage prevention techniques such as data leakage protection (DLP), digital right management (DRM), and system access control, etc. However, these techniques cannot effectively block the leakage of internal information by insiders who have a legitimate access authorization. The security system does not easily detect cases which a legitimate insider changes, deletes, and leaks data stored on the server. Therefore, we focused on the insider as the detection target to address this security weakness. In other words, we switched the detection target from objects (internal information) to subjects (insiders). We concentrated on biometrics signals change when an insider conducts abnormal behavior. When insiders attempt to leak internal information, they appear to display abnormal emotional conditions due to tension, agitation, and anxiety, etc. These conditions can be detected by the changes of biometrics signals such as pulse, temperature, and skin conductivity, etc. We carried out experiments in two ways in order to verify the effectiveness of the emotional recognition technology based on biometrics signals. We analyzed the possibility of internal information leakage detection using an emotional recognition technology based on biometrics signals through experiments.

• Journal of the Korean housing association
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• v.18 no.5
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• pp.33-43
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• 2007

This study aimed to analyze residential demands on intelligent systems for apartments and suggest space design directions of intelligent apartment complexes. Data collection was done through mail-in surveys by five respondent groups. Outcomes of this study would provide basic data for developing intelligent apartment housing corresponding to the residential characteristics and demands of the five respondent groups. The sample size for the questionnaire survey was 592. The types of the target residents in this study were classified into five categories; nuclear families, dual income families, single households and the handicapped needing special environmental supports, and workers at home who need the new home design with a home office. The primary findings of this study were as follows. 1) For the controllers of intelligent system, nuclear families preferred TV, single households prefer home-pad which is movable and provides access to the internet. Dual income families, the handicapped and workers at home preferred remote control panels. 2) For the desirable space for computer equipment, regardless of the types of target residents, bedroom and living room were preferred. 3) For the desirable space for a home theater system, most of respondent groups preferred living rooms, but many rather wanted to have media rooms only for this system.