• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.729-734
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• 2000

This paper proposes virtual-magnetic system by a force-reflecting interface to drive a ultrasonic motors(USMs) To approach virtual magnet in graphic the 6 dDOF force-reflecting interfaces provides force feedback to users as if I is magnetic-force, So users can feel real magnet Effectively to display the magnetic-force we need the interface with specific characteristics such as low inertia almost zero friction and very high stiffness As an actuator for the interface the USMs have many good advantage satisfied these conditions over conventional servo motors. To estimate capability of this virtual-magnetic system we did an experiment of magnetism based on coulomb's law when Coulmb's low apply this experiment it is vey conformable to real magnet

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3A
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• pp.287-295
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• 2011

Cognitive radio (CR) features opportunistic access to spectrum when licensed users (LU) are not operating. To avoid interference to LU, cognitive users (CU) need to perform spectrum sensing. Because of local shadowing, fading, or limited sensing capability, it is suggested that multiple CUs cooperate to detect LU. In cooperative spectrum sensing, CUs should exchange their sensing data with minimum bandwidth and delay. In this paper, we introduce a novel method to efficiently report sensing data to the central node in an infrastructured OFDM-based CR network. All CUs simultaneously report their sensing data over unique and orthogonal signals on locally available subcarriers. By detecting the signals, the central node can determine subcarrier availability for each CU. Implementation challenges are identified and then their solutions are suggested. The proposed method is evaluated through simulation on a realistic channel model. The results show that the proposed method is feasible and efficient.

• Journal of the Korean Professional Engineers Association
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• v.30 no.2
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• pp.79-86
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• 1997

As network has high speed and wide communication capability, users demand diverse and new software to satisfy their needs. To meet users needs, the softwares for multimedia or groupware or distributed virtual environments can communicate the widely distributed information fast and accurately. Even though the technology for this is under development, it is deficient to support the reliable computer communication. Distributed Object System aims, as the new paradigm of distributed system software development to overcome this problem, to obtain in distributed environment the easiness of development and management, expandability, reusability which object oriented technologies support by solving the complexity of communication processing through the object oriented methods. This paper aims to introduce distributed object system, its technological properties and the current status and trend of technology development related to its standardization. Additionally, with explaining the Replicated Shared Object System(RSOS) which is developed in our country as one of the distributed object systems, its future prospects and technical issues are discussed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.22-31
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• 2008

Cognitive radio should imply a proper sensing technique for detecting the presence of licensed users to identify the unused spectrum holes. Besides this, this information should also be used to opportunistically provide communication among secondary users. At the same time the performance of the primary user should not be declined by the secondary users. The detection of licensed users may be significantly difficult for shadowing effect. To prevail over this problem cooperative spectrum sensing, In which the combined observation information gained by multiple secondary users is employed to achieve higher performance of detection, has been inspected. However, the primary challenge of cooperative sensing lays in its ability to detect the presence of licensed user quickly and accurately. In this paper, we have used UltraWideBand (UWB) to detect the presence of licensed users and transmit the sensing information among the nodes of the network. UWB has the capability of transmitting data at a very high rate. It is unique in co-existence capability with narrow band systems. Here, we have shown that the detection probability of licensed user is improved by means of transmitting the spectrum sensing information via UWB. We also have analyzed the throughput of the proposed technique and compared the result with existing sensing method.

• Journal of Information Science Theory and Practice
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• v.7 no.1
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• pp.52-71
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• 2019

An insider threat is a threat that comes from people within the organization being attacked. It can be described as a function of the motivation, opportunity, and capability of the insider. Compared to managing the dimensions of opportunity and capability, assessing one's motivation in committing malicious acts poses more challenges to organizations because it usually involves a more obtrusive process of psychological examination. The existing body of research in psycholinguistics suggests that automated text analysis of electronic communications can be an alternative for predicting and detecting insider threat through unobtrusive behavior monitoring. However, a major challenge in employing this approach is that it is difficult to minimize the risk of missing any potential threat while maintaining an acceptable false alarm rate. To deal with the trade-off between the risk of missed catches and the false alarm rate, we propose a unified psycholinguistic framework that consolidates multiple text analyzers to carry out sentiment analysis, emotion analysis, and topic modeling on electronic communications for unobtrusive psychological assessment. The user scenarios presented in this paper demonstrated how the trade-off issue can be attenuated with different text analyzers working collaboratively to provide more comprehensive summaries of users' psychological states.

• The Journal of Society for e-Business Studies
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• v.14 no.2
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• pp.95-116
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• 2009

Ontologies have provided supports in integrating heterogeneous and distributed information. More and more ontologies and tools have been developed in various domains. However, building ontologies requires much time and effort. Therefore, ontologies need to be shared and reused among users. Specifically, finding the desired ontology from an ontology repository will benefit users. In the past, most of the studies on retrieving and ranking ontologies have mainly focused on lexical level supports. In those cases, it is impossible to find an ontology that includes concepts that users want to use at the semantic level. Most ontology libraries and ontology search engines have not provided semantic matching capability. Retrieving an ontology that users want to use requires a new ontology selection and ranking mechanism based on semantic similarity matching. We propose an ontology selection and ranking model consisting of selection criteria and metrics which are enhanced in semantic matching capabilities. The model we propose presents two novel features different from the previous research models. First, it enhances the ontology selection and ranking method practically and effectively by enabling semantic matching of taxonomy or relational linkage between concepts. Second, it identifies what measures should be used to rank ontologies in the given context and what weight should be assigned to each selection measure.

• Journal of the Ergonomics Society of Korea
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• v.34 no.5
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• pp.531-540
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• 2015

Objective: The objective of this research is to investigate the fundamentals of human computer interaction for wearable computers and derive technology requirements. Background: A wearable computer can be worn anytime with the support of unrestricted communications and a variety of services which provide maximum capability of information use. Key challenges in developing such wearable computers are the level of comfort that users do not feel what they wear, and easy and intuitive user interface. The research presented in this paper examines user interfaces for wearable computers. Method: In this research, we have classified the wearable user interface technologies and analyzed the advantages and disadvantages from the user's point of view. Based on this analysis, we issued a user interface technology to conduct research and development for commercialization. Results: Technology requirements are drawn to make wearable computers commercialized. Conclusion: The user interface technology for wearable system must start from the understanding of the ergonomic aspects of the end user, because users wear the system on their body. Developers do not try to develop a state-of-the-art technology without the requirement analysis of the end users. If people do not use the technology, it can't survive in the market. Currently, there is no dominant wearable user interface in the world. So, this area might try a new challenge for the technology beyond the traditional interface paradigm through various approaches and attempts. Application: The findings in this study are expected to be used for designing user interface for wearable systems, such as digital clothes and fashion apparel.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.214-222
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• 2002

Computer simulations are widely used to analyze passenger safety in simulated traffic accidents. ATB, Articulated Total Body, is a computer simulation model developed to predict gross human body response to such dynamic environments as vehicle crashes and pilot ejections. ATB, whose code is open, has high flexibility and application capability that users can easily insert defined modules and functions. ATB is, however, inconvenient as it was coded in FORTRAN and it needs a formated input file. Moreover, it takes much time to make input files and to modify coding errors. This study aims to increase user friendliness by adding a preprocessor program, WINATB(WINdows ATB), to the conventional ATB. WINATB, programmed in Visual C＋＋ and OpenGL, uses ATB IV as a dynamic solver. The preprocessor helps users prepare input files through graphic interface and dialog box. An additional postprocessor makes the graphical presentation of simulated results. In these case of the frontal crash, the rear impact and the side impact, the simulation results obtained by WINATB and MADYMO(MAthematical Dynamic Model) are compared to validate the effectiveness of WINAIB.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.9-13
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• 2001

This paper proposes the electric stimulus tactile apparatus system(TESTAS) loaded on the hap-tic interface using ultrasonic motors(USMs). To touch the virtual object like wall in graphic, the 6 DOF haptic interface provides force feedback to users as if it is real. But the case of sharp virtual object like a puncture, it could not provided the sense of pain, but only the reaction-force. After the TESTAS had been loaded on this haptic interface. it could Provide not only the force but also the pain to users. To estimate the capability of TESTAS, we did experiments of three cases, one was very sharp, another was dull, the other is continuative contact.

• Journal of KIISE:Software and Applications
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• v.36 no.1
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• pp.21-29
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• 2009

An intelligent service robot is a robot that monitors its surroundings, and then provides a service to meet a user's goal. It is normally impossible for a robot to anticipate all the needs of its user and various situations in the surroundings ahead, and to prepare for all the necessary functions to cope with them. Therefore, it is required to support the self-growing capability by which robots can extend their functionality based on users' needs and external conditions. In this paper, as an enabler of the self-growing capability, we propose a method that allows a robot to select a component-composition pattern represented in an architectural form (called a sub-architecture), and to extend its functionality by obtaining a set of software components that are prescribed in the pattern. Sub-architecture is selected and instantiated not only based on the functionality required but also based on quality requirements of a user and the surrounding environment. To provide this method, we constructed a quality-attributes-in-use ontology and developed a brokering mechanism that matches quality requirements of users and surroundings against quality attributes of sub-architectures. The ontology provides the common vocabularies to represent quality requirements and attributes, and enables the semantically-based reasoning in matching and instantiating appropriate sub-architectures in supporting services to users. This ontology-based approach contributes to provide a great flexibility in extending robot functionality based on available software components, and to narrow the gap between users' Quality requirements and the Quality of the actual services provided by a robot.