• Journal of Institute of Control, Robotics and Systems
• /
• v.18 no.2
• /
• pp.126-132
• /
• 2012

The technique for estimation of sound source direction is one of the important methods necessary for various engineering fields such as monitoring system, military services and so on. As a new approach for estimation of sound source direction, this paper propose the bio-mimetic localization sensor based on mechanically coupling structure motivated by hearing structure of fly, Ormia Ochracea. This creature is known for its outstanding recognition ability to the sound which has large wavelength compared to its own size. ITTF (Inter-Tympanal Transfer Function) which is the transfer function between displacements of the tympanal membranes on each side has the all inter-tympanal information dependent on sound direction. The peak and notch features of desired ITTF can be generated by using the appropriate mechanical properties. A example of estimation of sound source direction using generated ITTF with monotonically changing notch and peak patterns is shown.

• Proceedings of the KAIS Fall Conference
• /
• 2003.11a
• /
• pp.178-184
• /
• 2003

Case-based reasoning (CBR) often shows significant promise for improving effectiveness of complex and unstructured decision making. Consequently, it has been applied to various problem-solving areas including manufacturing, finance and marketing. However, the design of appropriate case indexing and retrieval mechanisms to improve the performance of CBR is still challenging issue. Most of previous studies to improve the effectiveness for CBR have focused on the similarity function or optimization of case features and their weights. However, according to some of prior researches, finding the optimal k parameter for k-nearest neighbor (k-NN) is also crucial to improve the performance of CBR system. Nonetheless, there have been few attempts which have tried to optimize the number of neighbors, especially using artificial intelligence (AI) techniques. In this study, we introduce a genetic algorithm (GA) to optimize the number of neighbors to combine. This study applies the new model to the real-world case provided by an online shopping mall in Korea. Experimental results show that a GA-optimized k-NN approach outperforms other AI techniques for purchasing behavior forecasting.

• The Research Journal of the Costume Culture
• /
• v.27 no.4
• /
• pp.336-352
• /
• 2019

This study examines the characteristics of expressing hippie styles in contemporary women's collections and analyzes them to benefit future fashion design and research. This study reviewed advanced research, fashion magazines, and information providers. The advanced research determined the study's scope by pinpointing the designers who introduced the hippie style into their collections. The results are as follows: First, the reproduced hippie style appears as the combination of various colors and materials, a convergence or mixture of styles, or the use of collage or patchwork. It employs natural silhouettes or varied colors and materials, which makes the renewed hippie style more luxurious than in the past. Second, the reproduced hippie style emphasizes and distinguishes between two types of femininity: a girlish, romantic image using A-line silhouettes and, bright, gleaming colors, and a sexy version that boldly exposes the body or women's curves and, uses soft and flexible materials. Third, the exotic tendencies found in the reproduced hippie style reflect the characteristics of the times, folk costume, or eastern or western features perceived as exotic. Recently, traditional costumes have changed slightly to recall characteristics found in the past. Fourth, the reproduced hippie style reflects hippies' affection for and interest in nature by using environmentally-friendly materials like natural fibers. Flowers, the symbol of hippies, appear most frequently.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4C
• /
• pp.295-307
• /
• 2002

The IEEE 1394 protocol is a de facto standard in multimedia digital home network. It supports several advanced features such as hot plugging, dynamic network reconfiguration, isochronous transmission and so on. Since the IEEE 1394 was adapted in the field of multimedia service with QoS guarantee, back bone network protocol with reel-time digital instrumentation and control sub networks, and physical layer protocol for real-time middleware such as real-time CORBA, the additional real-time features has been required in device driver implementation because of the necessity of the predictability enhancement. To guarantee the real-time features, the device driver of the IEEE 1394 should support the priority based packet processing and also need a isochronous buffer management mechanism to deal with the periodic isochronous communication. In this paper, we proposed a new software architecture of the IEEE 1394 device driver for supporting the real-time characteristics such as priority based packet processing, priority based scheduling and so on.

• Nuclear Engineering and Technology
• /
• v.45 no.5
• /
• pp.625-636
• /
• 2013

Pressing demands of economic competitiveness, the need for large-scale deployment, minimizing the need of human intervention, and experience from the past events and incidents at operating reactors have guided the evolution and innovations in reactor technologies. Indian innovative reactor 'AHWR' is a pressure-tube type natural circulation based boiling water reactor that is designed to meet such requirements, which essentially reflect the needs of next generation reactors. The reactor employs various passive features to prevent and mitigate accidental conditions, like a slightly negative void reactivity coefficient, passive poison injection to scram the reactor in event of failure of the wired shutdown systems, a large elevated pool of water as a heat sink inside the containment, passive decay heat removal based on natural circulation and passive valves, passive ECC injection, etc. It is designed to meet the fundamental safety requirements of safe shutdown, safe decay heat removal and confinement of activity with no impact in public domain, and hence, no need for emergency planning under all conceivable scenarios. This paper examines the role of the various passive safety systems in prevention and mitigation of severe plant conditions that may arise in event of multiple failures. For the purpose of demonstration of the effectiveness of its passive features, postulated scenarios on the lines of three major severe accidents in the history of nuclear power reactors are considered, namely; the Three Mile Island (TMI), Chernobyl and Fukushima accidents. Severe plant conditions along the lines of these scenarios are postulated to the extent conceivable in the reactor under consideration and analyzed using best estimate system thermal-hydraulics code RELAP5/Mod3.2. It is found that the various passive systems incorporated enable the reactor to tolerate the postulated accident conditions without causing severe plant conditions and core degradation.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2001.01a
• /
• pp.448-455
• /
• 2001

Recently, many enterprises have attempted to capitalize knowledge assets on data warehouse (DW). It has been recognized as strategic core process to create corporate competitive advantage and implement enterprise e-biz strategies. However, most approaches to represent knowledge and decision process have limits in considering various knowledge types, their relationships and continuity in knowledge formulation. In addition, they are so inclined to one side such as concept-oriented frameworks or technology-oriented ones. They lack universal and wide-ranging features. This paper presents a comprehensive methodology to accumulate knowledge capital on DW via a properly grained hypermedia model. The methodology consists of three phases: knowledge requirement elicitation, hypermedia modeling, and system implementation. A real-life case for medical DW development is presented to demonstrate the usefulness of the proposed methodology. This methodology is effective when an organization accumulates knowledge assets to put the corporate e-biz or cre-biz strategy into practice.

• Proceedings of the KIPE Conference
• /
• 2011.07a
• /
• pp.498-499
• /
• 2011

In this paper, the fundamental features of the arc stability DC arc furnace have been investigated, from the converter point of view. To compare of measurement arc data from DC arc furnace and the advanced arc simulations of magneto-hydrodynamics (MHD) and the well known Cassie-Mayr arc model have been extensively used. The MHD based arc simulation has been validated in the subcomponent level, for the free burning arc set up in the laboratory. The arc simulation predicted the arc voltage for different currents with the accuracy which satisfies engineering requirements. It has been shown that the arc current steepness at current zero determines the arc stability, and the associated peak arc resistance can be used as its quantitative measure. Based on the presented insight into the DC arc stability, a converter topology solution which realizes an optimal arc stability has been proposed. The main results presented in this paper provide a design guideline for the future DC arc furnace converter topology developments.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.1
• /
• pp.13-21
• /
• 2004

In the design of superconducting cable systems, quench analysis have to be advanced for applying to a real systems. It is necessary to calculate the current, voltage and resistance during the quench. Simulation program named EMTDC was used to analyze the quench state. Normal zone evaluation and quench development with EMTDC are one of the major features of quench analysis. This paper presents the two kinds of quench control models which are the Switch Control Type and the Fortran Control Type. In case of the quench developing area, the simplicity cable model consist of resistance, inductance and capacitance. The impedance of the pipe type superconducting cable is calculated by numerical analysis method. The resistance and inductance increased during quench. However the variation have an effect on the fault current. The voltage was also developed by resistance and inductance. This paper presents the relationship between the current. voltage, resistance and inductance during quench.

• Journal of Electrochemical Science and Technology
• /
• v.7 no.1
• /
• pp.1-12
• /
• 2016

The production of oxygen and hydrogen from solar water splitting has been considered to be an ultimate solution for energy and environmental issues, and over the past few years, nano-sized semiconducting metal oxides alone and with graphene have been shown to have great promise for use in photocatalytic water splitting. It is challenging to find ideal materials for photoelectrochemical water splitting, and these have limited commercial applicability due to critical factors, including their physico-chemical properties, the rate of charge-carrier recombination and limited light absorption. This review article discusses these main features, and recent research progress and major factors affect the performance of the water splitting reaction. The mechanism behind these interactions in transition metal oxides and graphene based nano-structured semiconductors upon illumination has been discussed in detail, and such characteristics are relevant to the design of materials with a superior photocatalytic response towards UV and visible light.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.285-288
• /
• 2007

In the recent years the using of low-density material such as high-strength Al alloy on the various industries is becoming light-weight. High strength and hollow Al alloy is good material for stiffness and recycling. Therefore the advanced manufacturing technology with Al alloy is continuously required in many industrial fields. In this study simplified hallow rectangular section of Al alloy is analyzed by FE analysis. Bending stress is affected punching and rotating of wing-die. The analysis of press bending is preformed at first. The elastic recovery value of component and stress distribution acting from the result of the bending angle of three types were obtained. The designed precesses were analyzed by the commercial FE code, Deform-3D. Forming dies for each process were designed and prototypes were manufactured by the verified forming process. Some of the important features of design parameters in the press bending were reviewed.