Earticle

유헬스케어 환경에서는 M2M 기반에서 중요한 생체정보가 처리된다. M2M은 주로 무선네트워크를 기반으로 하는데, 무선네트워크는 제한된 대역폭과 낮은 신뢰성 등 극복해야할 과제가 많이 있다. 본 논문에서는 이 과제를 데 이터 전송효율을 높여 해결하고자 하였으며, 생체정보에 대한 높은 압축특성을 갖는 uHLZW(u-Healthcare LZW) 압축 알고리즘을 제안하였다. 실험결과 기존의 압축알고리즘에 비해 1.6배에서 4배정도 압축효율이 개선됨을 알 수 있었다.

In u-Healthcare environment, large amounts of important vital information is processed through M2M(Machine to Machine). M2M is configured by wireless networks and has several problems for limited bandwidth and low reliability. Therefore, in this paper is proposed a method called uHLZW(u-Healthcare LZW) to improve channel efficiency to solve such problem. uHLZW algorithm has high compression ratio for vital data. The results showed that the average compression ratio of uHLZW got from 1.6 times to 4.0 times better than existing methods(Huffman and LZW compression).

u-Healthcare 환경에서는 많은 양의 중요한 의료정보가 무선을 통해 처리된다. 따라서 데이터를 전송하는 네트워크 시스템의 효율 개선이 필요하다. 이 논문은 u-Healthcare 환경에서 ECG 데이터를 효율적으로 전송하기 위한 압축 솔루션(ECGLZW)을 제시한다. 실험 결과, ECGLZW의 평균 압축률은 4.6으로써, 기존의 압축 방식(Huffman 압축 방식과 LZW 압축 방식)에 비해 200% 정도 효율이 개선됨을 알 수 있다. ECGLZW의 높은 압축률로 무선채널의 효율이 개선되고, 이를 네트워크 오류에 대한 재전송 및 암호화에 활용함으로써 데이터에 대한 신뢰성 및 u-Healthcare 정보에 대한 보안을 강화할 수 있다.

In u-Healthcare environment, large amounts of important medical information is processed through wireless communication. Therefore there is a need to increase the efficiency of the network system of sending ECG data. This paper presents a compression solution for efficient ECG data transmission(ECGLZW) in u-Healthcare environment. The results showed that the average compression ratio of ECGLZW was 4.6, which got 200% better than existing methods(Huffman and LZW compression). ECGLZW's high compression ratio can increase the efficiency of wireless channels. As a result, reliable communication and security of u-Healthcare information could be achieved by applying these remaining channels to retransmission and encryption.

Poly(lactide) (PLA)-coated paperboards were prepared by solution coating and thermo-compression coating methods and their effect of coating on the packaging properties such as tensile, water resistance, water vapor barrier, and heat sealing properties was tested. Compared with uncoated control paperboard, tensile strength (TS) of PLA-coated paperboard increased profoundly (2.2-2.6 folds) with slight increase in elongation at break (E). Water absorptiveness (WA) of the paperboard decreased 74-170 folds and water vapor permeability (WVP) decreased 6.3-22.1 folds by coating with PLA, which indicates an increase in the hydrophobicity of the surface of paperboard. Compared with polyethylene (PE)-coated paperboard, both PLA-coated paperboard exhibited 2.3 time higher heat sealing strength. In addition, the PLA-coated paperboards showed equal or higher wet TS than PE-coated paperboard. All the test results showed that the paperboard coated by the thermo-compression coating method was similar to or better than those of coated by the solution coating method.

The pultruded structural shapes are usually composed of thin-walled plate elements. Because the composite material has relatively low elastic moduli, the design of pultruded compression members may not be governed by the material strength limit state but by the stability limit state such as the local buckling or the global buckling. Therefore, the stability limit state must be checked to design pultruded columns. In this research, the local buckling analysis of pultruded I-shape column was conducted for various composite materials using the closed-form solution. To establish the design guidelines for the local buckling of pultruded I-shape compression members, the simplified form of equation to find the local buckling coefficient of pultruded I-shape column was proposed as a function of mechanical properties and the width ratio of plate components using the results obtainde by the closed-form solution. In order to verify the validity of proposed solution, the results obtained by the proposed approximate solution were compared with those of the closed-form solution and the experimental results.

To investigate the deformation properties of TiC-(5-20) mol% Mo solid solution single crystals at high temperature by compression testing, single crystals of various compositions were grown by the radio frequency floating zone technique and were deformed by compression at temperature from 1250K to 2270K at strain rates from $5.1{\times}10^{-5}$ to $5.9{\times}10^{-3}/s$. The plastic flow property of solid solution single crystals was found to be clearly different among a three-temperature range (low, intermediate and high temperature ranges) whose boundaries were dependent on the strain rate. From the observed property, we conclude that the deformation in the low temperature range is controlled by the Peierls mechanism, in the intermediate temperature range by the dynamic strain aging and in the high temperature range by the solute atmosphere dragging mechanism. The work softening tends to become less evident with an increasing experimental temperature and with a decreasing strain rate. The temperature and strain rate dependence of the critical resolved shear stress is the strongest in the high temperature range. The curves are divided into three parts with different slopes by a transition temperature. The critical resolved shear stress (${\tau}_{0.2}$) at the high temperature range showed that Mo content dependence of ${\tau}_{0.2}$ with temperature and the dependence is very marked at lower temperature. In the higher temperature range, ${\tau}_{0.2}$ increases monotonously with an increasing Mo content.

Fiber reinforced polymeric plastic (FRP) materials have many advantages over conventional structural materials, i.e., high specific strength and stiffness, high corrosion resistance, right weight, etc. Among the various manufacturing methods, pultrusion process is one of the best choices for the mass production of structural plastic members. Since the major reinforcing fibers are placed along the axial direction of the member, this material is usually considered as an orthotropic material. However, pultruded FRP (PFRP) structural members have low modulus of elasticity and are composed of orthotropic thin plate components the members are prone to buckle. Therefore, stability is an important issue in the design of the pultruded FRP structural members. Many researchers have conducted related studies to publish the design method of FRP structures and recently, referred to the previous researches, pre-standard for LRFD of pultruded FRP structures is presented. In this paper, the accuracy and suitability of design equation for the local buckling strength of pultruded FRP I-shape compression members presented by ASCE are estimated. In the estimation, we compared the results obtained by design equation, closed-form solution, and experiments conducted by previous researches.