• World Technopolis Review
• /
• 제5권2호
• /
• pp.98-107
• /
• 2016

By highlighting the efficiencies gained from regional specialization, the cluster concept has distracted economic development officials from their traditional role of diversifying regional and local economies. Clustering was a viable strategy for much of the 18 years following its original appearance in the literature. Now, two events cast doubt on the continued viability of cluster-based specialization. First, the digital convergence has blurred the boundaries that once separated one industry from another. An industry cluster strategy becomes difficult when the industry cannot be defined. Second, many cluster initiatives fail. Combining literature search with the system-theoretic notions of efficiency and redundancy, we find many factors moderate cluster success. This implies regions facing uncertain success in their cluster-building efforts should thoroughly understand their unique circumstances and build upon them. Regions with successful clusters are advised to aim for multiple related clusters or superclusters.

• Bulletin of the Korean Chemical Society
• /
• 제30권9호
• /
• pp.2098-2100
• /
• 2009

A new tetrahydroanthracene, 3,6,9-trihydroxy-3,4-dihydroanthracen-1(2H)-one (1), six phenolics, moscatilin (2), gigantol (3), batatasin (4), moscatin (5), 9,10-dihydromoscatin (6), 10-dihydrophenanthrene-2,4,7-triol (7), and a sesquiterpenoid, corchoionoside C (8), together with two sterols $\beta$-sitosterol (9) and daucosterol (10), were isolated from the stems of Dendrobium polyanthum. Compounds 1 and 2 were assessed for cytotoxic activity against two human tumor cell lines (A549 and HL-60).

• Applied Biological Chemistry
• /
• 제33권3호
• /
• pp.257-260
• /
• 1990

김치 숙성도 판정을 위하여 $25^{\circ}C$에서 김치를 발효시키면서 생성되는 이산화탄소를 soda lime에 흡착시키면서 6시간 간격으로 무게 증가율을 측정하였다. 발효 36시간경에 무게 증가율이 최대값을 나타내었는데, 이는 pH, 적정 산도 및 관능 검사의 결과와 비교했을 때 김치의 숙성 적기와 비교적 잘 일치하였다. 따라서 이 방법은 김치의 숙성도를 판정하는 데 유효한 것으로 사료된다.

• Journal of Electrical Engineering and Technology
• /
• 제6권4호
• /
• pp.519-526
• /
• 2011

An investigation of the mechanism of period-doubling bifurcation in a voltage mode controlled buck-boost converter operating in discontinuous conduction mode is conducted from the viewpoint of nonlinear dynamical systems. The discrete iterative model describing the dynamics of the close-loop is derived. Period-doubling bifurcation occurs at certain values of the feedback factor. Results from numerical simulations and experiments are provided to verify the evolution of perioddoubling bifurcation, and the results are consistent with the theoretical analysis. These results show that the buck-boost converters exhibit a wide range of nonlinear behavior, and the system exhibits a typical period-doubling bifurcation route to chaos under particular operating conditions.

• 생약학회지
• /
• 제32권4호통권127호
• /
• pp.322-326
• /
• 2001

For the quality control of Leonuri Herba, alkaloid compound, leonurine, was isolated from the MeOH extract of Leonurus sibiricus L. (Labiatae) and identified by the spectroscopic analysis. A quantitative analysis of leonurine using HPLC method showed that the average contents were $0.124{\pm}0.065%$ in 34 samples collected throughout the regions of Korea.

• Tribology and Lubricants
• /
• 제21권6호
• /
• pp.263-267
• /
• 2005

The tribological performance of multi-walled carbon nanotubes (MWNT) in mineral oils is investigated at ambient temperature. The frictional forces, wear amounts and cycles to scuffing of the oils with nanotubes and without those were measured using the ball-on-disk tester. It was found that there were little differences in the frictional forces and wear amounts of two oils. However, the scuffing times of oils with nanotubes were much longer than those of oils without nanotubes in sliding tests. The nanotubes were very effective on maintaining the oil gap and protecting the surfaces in boundary lubricated sliding.

• Journal of Mechanical Science and Technology
• /
• 제18권6호
• /
• pp.946-954
• /
• 2004

A model in the form of a Bearing Load Distribution (BLD) matrix in the Multi Bearing Rotor System (MBRS) is established by a transfer matrix equation with the consideration of a bearing load, elevation and uniform load distribution. The concept of Bearing Load Sensitivity (BLS) is proposed and matrices for load and elevation sensitivity are obtained. In order to share MBRS design resources on the Internet with remote customers, the basic principle of Remote Computing (RC) based on the Internet is introduced ; the RC of the BLD and BLS is achieved by Microsoft Active Server Pages (ASP) technology.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권10호
• /
• pp.3508-3519
• /
• 2014

The use of a smartphone with one hand has been getting difficult as the size of the smartphone display gets larger. In addition, people handicapped or using one hand for handling other pieces may encounter difficulties to touch exact numbers for calling with their smartphones. Thus, motion-tracked speed dialing can be a good solution for these cases and also an advanced feature applicable in the future network not requiring dedicated Internet connections. The previous study on this feature showed a result with a limitation of using servers connected via Internet connections for solving real-time control issues. Therefore, this paper proposes a scheme for the smartphone dialing on motion-tracked numbers without any servers or Internet connections, and presents the details of its implementation and results.

• Transactions on Electrical and Electronic Materials
• /
• 제17권2호
• /
• pp.109-112
• /
• 2016

We demonstrated an alternative electrically controlled birefringence liquid crystal (ECB-LC) system with ion beam (IB)-irradiated yttrium gallium oxide (YGaO) alignment films using a sol-gel process. The surface roughness of the films was dependent on the annealing temperature; aggregated particles on surface were observed at lower annealing temperatures, whereas a smooth surface could be obtained with higher annealing temperatures. Higher transmittance in the visible region was observed at higher annealing temperatures. The film had an amorphous crystallographic state irrespective of the annealing temperature. Furthermore, ECB-LC cell with our IB-irradiated YGaO film yielded faster response time when compared to ECB-LC cell with rubbed polyimide. Considering the fast response time and high transmittance, the IB-irradiated YGaO-base LC system is a powerful alternative application for the liquid crystal display industry.

• Tribology and Lubricants
• /
• 제21권1호
• /
• pp.16-20
• /
• 2005

Friction and wear characteristics between two steel surfaces under fretting condition are investigated experimentally. The fretting damage caused by low-amplitude oscillatory sliding can be classified into three regimes of gross-slip, mixed-slip and partial-slip due to stick-slip phenomenon. One of the most important characteristics of fretting wear is the transition from gross-slip to mixed-slip. This study was focused on getting the degree of stick-slip out of the friction transition under fretting condition. Fretting wear is divided into three conditions of gross-slip/mixed-slip/partial-slip. The criteria for the division are friction and displacement amplitude, wear scar morphology and dissipated energy. In this test, friction force and displacement were measured for detecting the transition from mixed-slip to gross-slip and qualitatively predicting the degree of the wear.