• KIPS Transactions on Computer and Communication Systems
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• v.4 no.6
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• pp.197-204
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• 2015

Recent changes in health care environment including aging population and prevalence of chronic disease encourage the adoption of new innovative technological solutions including wearable vital sensors, wireless networks, and smart phone. In this paper, we present an effective at-home lifestyle monitoring system that can be used for self-management and health intervention of patient himself in the Management-by-Exception perspectives. We implemented the filtering and queuing algorithms as a preprocessor of monitoring system to enhance efficiency of proposed system, and the effective UX design for self-management of patients themselves. The 94,467 actual clinic data was used to test the efficiency of the proposed system. As as a result, 64.8% of the incoming vital data was identified to be filtered out.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.466-474
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• 2014

This paper presents the line contention avoidance experiments with an optical switch, which was selected based on the comparison analysis and evaluation of the various characteristics. For example, the function, structure, strengths and weaknesses of the optical switches. After considering the nonblocking, modularity, upgrade ability and optical power loss of the several kind of the switch fabrics, a switch was selected. The selected switch fabric by using wavelength converters was controlled to avoid contention of the optical lines. In this experiment shows an example of three cases. As a result of this experiment, optical signal shows a changed peek of optical power in output. By showing a peak it confirms that the contention was avoided. By analyzing of changed optical power according to the channel setting time and release time to control of the switch could be determined. If this analysis applied to the network design, economical and efficient structures can be formed.

• Clean Technology
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• v.10 no.1
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• pp.9-17
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• 2004

Direct methanol fuel cell(DMFC) with proton exchange membrane (PEM) has advantages over the conventional power source (e.g. vehicle). DMFC, however, has a problem to be solved such as methanol crossover, high anodic overpotential and limiting current density, etc. The physicochemical phenomena in DMFC can be described by coupled PDEs (partial differential equations), which can be solved by a PDE solver. In this paper, we utilized a commercial software FEMLAB to solve the PDEs. The FEMLAB is one of the software programs available which are developed as a solver for building physics problems based on PDEs and is designed to simulate systems of coupled PDEs which may be 1D, 2D, 3D, non-liner and time dependent. We performed simulation using the Tafel equation as an electrochemical reaction model to analyze methanol concentration profile in DMFC system. We confirm that the rapid decrease of methanol concentration at anodic catalyst layer with the increase of the current density is a main reason of the low performance in DMFC through simulation results.

• Journal of Korea Spatial Information System Society
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• v.7 no.1 s.13
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• pp.53-62
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• 2005

A challenging task in the LBS system engineering is to implement a highly scalable system architecture which can manage moderate-size configurations handling thousands of moving items as well as upper-end configurations handling distributed computing system architecture that consists of multiple data processors, each dedicated to keeping records relevant to a different geographical zone and a different time zone. In this paper, we explain a prototype location data server structuring major components of GALIS by employing the TMO programming scheme, including the execution engine middleware developed to support real-time distributed object programming and real-time distributed computing system design. We present how to generate realistic location sensing reports and how to process such location reports and location-related queries. Some experimental results showing performance factors regarding distributed query processing are also explained.

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.107-112
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• 2003

This paper describes a new simple QRS detection algorithm using index function based on resonance theory. The ECG signal can be modeled with several sinusoidal pulses and its first difference has some relations with the amplitude and frequency of sinusoidal pulse. Based on above fact, an index function, similar to the square of the imaginary part of a simple R-L-C circuit, was designed. A QRS complex is detected by applying the adaptive method to the response of index function. The algorithm showed a performance comparable to or higher than the other algorithms. Because it does not require any complicated preprocessing or postprocessing, it can be implemented in real time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.704-711
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• 2003

Recently, the demands for real-time service and multimedia data are rapidly increasing. There are significant redundancies between header fields both within the same packet header and in consecutive packets belonging to the same packet stream. But there are many overheads in using the current UDP/IP protocol. Header compression is considered to enhance the transmission efficiency for small size of payload. By sending the static field information only once initially and by utilizing dependencies and predictability for other fields, the header size can be significantly reduced for most packets. This work describes an implementation for header compression of the headers of U/UDP protocols to reduce overhead on Ethernet network. Typical UDP/IP Header packets can be compressed down to 7 bytes and the header compression system is designed and implemented on the Linux environment. Using the designed Header compression system between a server and a client have the advantage of effective data throughput in network.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.452-457
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• 2015

Recently, wearable devices have gained popularity with familiar form factors and designs of eye-wear and watch to satisfy wearers' various preferences. Since UI/UX of smartphones can not be applied directly on smaller wearable devices, text entry on wearable devices is still problematic. In this paper, we first identify UI/UX problems of existing input methods and propose a new input method for wearable devices specifically targeting smartwatch platforms. We design and implement an efficient text entry method for wearable devices using trackball sensor and evaluate its performance and usability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.215-224
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• 2010

A container security device (CSD) monitors intrusions through the cargo door; it is a reduced function device that uses IEEE 802.15.4 with a beacon mode. However, in the beacon mode, the CSD consumes too much battery power in periodical idle listening and sensing trials. Moreover, the CSD cannot send the message to the CSD reader actively, and it makes big latency problem. Therefore, we propose a low-power CSD to reduce the unnecessary power consumption. The proposed CSD follows the requirements of the U.S. Department of Homeland Security, and reduces battery consumption through a power-efficient hardware design, a night-watch mechanism for low-power operation and low-power sensing to reduce unnecessary monitoring. And the CSD sends alert message to the CSD reader. Simulation results show that our CSD reduces battery consumption by over 70% through the night-watch mechanism and by approximately 80% through the low-power sensing. And the CSD can send the alert message to the remote CSD reader by over 94%.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2002.05a
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• pp.131-131
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• 2002

종이가 인류의 생활에 미치는 비중은 정보의 전달을 제 l의 목적으로 사용되고 있는 인쇄용 지와 필기용지가 차지하는 것이 가장 크다. 정보전달의 매개로 사용되는 종이의 용도 이외 의 것을 살펴보면 전사지, 감압.감열지, 절연지,OMR지, 항공권지, 벽지 등과 같은 특수지와 기능지가 있다. 특히 벽지는 다양한 문양과 색감으로 인간의 미적 감각과 정신적 안정감에 미치는 영향이 크다. 벽지의 기능은 여러 가지의 목적으로 우리들의 실생활에 있어서 없어서는 안될 중요한 건축 재료로서 사용되고 있다. 가장 중요한 벽지의 목적은 앞서 언급한 바와 같이 미려한 색상과 다양한 디자인으로 도안.인쇄 및 발포 처리된 벽지를 사용하여 단순한 벽면을 개인의 취향 에 맞게 함으로써 심리적 안정감을 가져옴과 동시에 미적 가치를 증가 시켜 문화 수준의 향 상에도 영향을 미치는 것으로 알려져 있다. 그러나 종이 벽지와 종이 벽지 원지를 기저로 하여 제조된 발포 벽지는 인화성이 강하기 때 문에 이들에 대한 적절한 난연 처리가 요구 되고 있다. 매년 발생되는 다양한 형태의 화재 는 돌이킬 수 없는 인명과 재산의 손실로 귀결되어 각별한 주의가 요구되기 때문에 주거공 간과 대중의 군집이 많이 이루어지는 공공장소에서의 난연 처리된 벽지 사용에 대한 중요성 이 나날이 그 강도를 더 해가고 있는 실정이다. 난연 처리된 벽지는 통상적인 벽지에 비하 여 제조 원가의 상승에 따라 가격이 비싸기 때문에 일반인들에게 있어서 그 사용은 주목할 정도로 증가되지 못하고 있으나, 생활 수준이 향상 될수록 안전에 대한 의식 강화와 정부의 노력으로 인하여 그 사용량은 크게 늘어날 것으로 기대된다. 따라서 본 연구에서는 종이의 제조에 사용되는 원지의 충전제 종류와 양 그리고 난연 처리 된 폴리에스테르 섬유의 혼합을 달리하여 제조된 원지를 사용하여 난연 처려한 후 이들의 인화 특성에 대해 고찰 함으로써 보다 향상된 성능을 발휘 할 수 있는 난연 벽지의 제조와 개발에 보탬이 되고자 하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.12
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• pp.49-57
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• 2001

In this paper, equivalent circuit model and novel model parameter extraction method of a silicon(Si) substrate are presented. Substrate coupling through Si-substrate is quantitatively investigated by analyzing equivalent circuit with operating frequency and characteristic frequencies (i.e., pole and zero frequency) of a system. For the experimental verification of the equivalent circuit and parameter extraction method, test patterns are designed and fabricated in standard CMOS technology with various isolation distances, substrate resistivity, and guard-ring structures. Then, these are measured in l00MHz-20GHz frequency range by using vector network analyzer. It is shown that the equivalent-circuit-based HSPICE simulation results using extracted parameters have excellent agreement with the experimental results. Thus, the proposed equivalent circuit and parameter extraction methodology can be usefully employed in mixed-signal circuit design and verification of a circuit performance.