• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.1
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• pp.14-21
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• 1995

General Mechanical Structures have various and complex vibration transmission paths. In order to identify the mechanism of vibration transmission. The correct estimation of exciation forces and the exact modeling of transmission paths are required. In this paper, vector synthesis technique is employed to identify the characteristics of vibration input and it's transmission to body structure for the mounting system of a compressor in a refrigerator. Vibration reduction efficiency of each transmission path is evaluated by comparing individual vector components obtained before and after the paths from experimental research. The degree of effect is used to estimate the contribution of vibration input components to total output. And this paper presents a new technique based on simulation studies using vector synthesis dragram, by which the effects of change of the magnitude and phase of transmission paths can be predicted.

• Journal of Conservation Science
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• v.31 no.1
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• pp.65-73
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• 2015

The purposes of this study are helping the understanding on the Dae-hwe kind relics, verifying the deformation rate stability during conservation treatment and enhancing the conservation treatment work by investigating the status and analyzing the material of Taejo's portrait mounting decorative knots in the National Palace Museum of Korea collection. The result of material analysis on the decorative knots was that the outer threads are silk threads, inner threads are cotton threads, the width of the metal threads was $500{\sim}600{\mu}m$ and the major component of it was 55wt% copper. The result of verification on the deformation rate during the form correction of the bell tassel was that it has been found as stable by having the deformation rate of 1 TPCM or less. The result of glue selection test to be used on the repairing of tassel cross-section with its thread cut was that wheat starch adhesive has been found most appropriate because it has the highest tensile strength at all concentrations. The conservation and treatment procedure was established based on above results of analysis and test on the relic and the conservation treatment work including packaging has been completed in accordance with the established procedure.

• International Commerce and Information Review
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• v.12 no.4
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• pp.303-325
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• 2010

This study concerns the identification of INPR process (i.e., antecedents, timeliness in new product development (NPD) and international new product rollout (INPR) and consequences) for international new product performance. It was empirically tested by a Korean sample to verify the validity of the research framework. The results show that cross-functional integration exhibited a statistically significant and positive effect on NPD timeliness. For the rapid development of new products, evidence is mounting in favor of cross-functional integration that facilitates both the quick dissemination and utilization of information. A higher level of marketing synergy was positively associated with a higher level of NPD timeliness. These findings suggest that marketing synergy plays a key role in enhancing NPD timeliness in South Korean manufacturing companies. The results also indicate that HQ-subsidiary cooperation was positively related to INPR timeliness. More comprehensive and varied information flows between HQ and subsidiary are likely to achieve product competitive advantage and then the latter may lead to international new product launch timeliness. However, technology synergy has no significant influence on NPD timeliness, implying that Korean manufacturers' managers do not recognize technology to be a major driving force, unlike Western manufacturers' managers. The findings also indicate that the positive effects of timeliness in INPR on international new product performance. It is important note that successful achievements of international new product success are likely to rely on INPR timeliness. Importantly, the results found that products developed within planned time frames are more likely to be rolled out into multi-markets on-time, resulting in higher levels of performance than when NPD completion is delayed.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.7-14
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• 2018

In this study, a new check valve was studied to improve the load pressure of a brake system with a small piezoelectric-hydraulic pump. During the pressurization process, the steady-state pressure at the load is affected by the ratio of the cross-sectional area of the check valve the chamber pressure and load pressure. Since the flow path cover of the check valve is made wider than the cross-sectional area of the output flow to prevent backflow, a method of reducing the area ratio is proposed for a higher load pressure by mounting an additional mass to a thin plate spring type check valve. To identify the effect of mounting an additional mass to the existing check valve on the load pressure, a simple brake system with a small piezoelectric-hydraulic pump was modeled using a commercial code AMESim. The AMESim modeling was verified by comparing the simulation results with the experimental results of the pump the existing check valve. The additional mass was added to the verified AMESim modeling and higher load pressure was able to be obtained through simulation. The 35% performance improvement in load pressure identified by carrying out pressurization test of the brake system after adopting the new check valve the small piezoelectric-hydraulic pump.

• International Journal of Fluid Machinery and Systems
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• v.5 no.2
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• pp.91-99
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• 2012

The Fighter aircraft transmission system consists of a light weight, High Speed Flexible Coupling (HSFC) known as Power Take-Off shaft (PTO) for connecting Engine gearbox (EGB) with Accessory Gear Box (AGB). The HSFC transmits the power through series of specially contoured metallic annular thin flexible plates whose planes are normal to the torque axis. The HSFC operates at high speed ranging from 10,000 to 18,000 rpm. The HSFC is also catered for accommodating larger lateral and axial misalignment resulting from differential thermal expansion of the aircraft engine and mounting arrangement. The contoured titanium alloy flexible plates are designed with a thin cross sectional profile to accommodate axial and parallel misalignment by the elastic material flexure. This paper investigates the effect of misalignment on the transmission characteristics of the HSFC couplings. A mathematical model for the HSFC coupling with misalignment has been developed for analyzing the torque transmission and force interaction characteristics. An extensive testing has been conducted for validating characteristics of the designed coupling under various misalignment conditions. With this the suitability of the model adapted for the design iteration of HSFC development is validated. This method will reduce the design iteration cycles of HSFC and can be extended for the similar development of flexible couplings.

• Journal of Drive and Control
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• v.12 no.4
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• pp.35-40
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• 2015

A gas spring provides support force for lifting, positioning, lowering, and counterbalancing weights. It offers a wide range of reaction force with a flat force characteristic, simple mounting, compact size, speed controlled damping, and cushioned end motion. The most common usage is as a support on a horizontally hinged automotive tail gate. However, its versatility and ease of use has been applied in many other industrial applications ranging from office equipment to off-road vehicles. The cylinder of a gas spring is filled with compressed nitrogen gas, which is applied with equal pressure on both sides of the piston. The surface area of the rod side of the piston is smaller than the opposite side, producing a pushing force. The magnitude of the reaction force is determined by the cross-sectional area of the piston rod and the internal pressure inside the cylinder. The reaction force is influenced by many design parameters such as initial chamber volume, diameter ratio, etc. In this paper, we investigated the reaction force characteristics and carried out parameter sensitivity analysis for the design parameters of a gas spring.

• Molecules and Cells
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• v.26 no.4
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• pp.329-337
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• 2008

Src-family kinases are critically involved in the control of cytoskeleton organization and in the generation of integrin-dependent signaling responses, inducing tyrosine phosphorylation of many signaling and cytoskeletal proteins. Activity of the Src family of tyrosine kinases is tightly controlled by inhibitory phosphorylation of a carboxy-terminal tyrosine residue, inducing an inactive conformation through binding with its SH2 domain. Dephosphorylation of C-ter tyrosine, as well as its deletion of substitution with phenylalanine in oncogenic Src kinases, leads to autophosphorylation at a tyrosine in the activation loop, thereby leading to enhanced Src activity. Beside this phophorylation/dephosphorylation circuitry, cysteine oxidation has been recently reported as a further mechanism of enzyme activation. Mounting evidence describes Src activation via its redox regulation as a key outcome in several circumstances, including growth factor and cytokines signaling, integrin-mediated cell adhesion and motility, membrane receptor cross-talk as well in cell transformation and tumor progression. Among the plethora of data involving Src kinase in physiological and pathophysiological processes, this review will give emphasis to the redox component of the regulation of this master kinase.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.158-165
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• 2007

In this paper, the circularly polarized $4{\times}4$ array antenna is proposed for the X-band. A single antenna consists of square patch and unequal cross-aperture coupled feeding. The RHCP(Right Handed Circularly Polarization) is generated by unequal cross-aperture coupled feeding. By reducing space among elements of way antenna from 0.8 ${\lambda}_0$ to 0.45 ${\lambda}_0$, the mounting area of array antenna is miniaturized. The $2{\times}2$ array antenna is designed using sequential rotation feeding network. The good level of gain, axial ratio, and impedance bandwidth are achieved. The $4{\times}4$ array antenna is extended by ${\lambda}/4$ transformer and T-junction power divider. The simulated maximum radiation gain is 15.09 dBi at 10 GHz. The simulated 3 dB Axial Ratio bandwidth is from 9.05 to 10.4 GHz(13.5%). Also the measured impedance bandwidth($VSWR{\leq}2$) of manufactured $4{\times}4$ array antenna is from 8.45 to 11.84 GHz(33.9%). The measured maximum radiation gain is 11.10 dBi at 10 GHz. The measured 3 dB Axial Ratio bandwidth is from 9.42 to 10.47 GHz(10.5%).

• Journal of the Korea Convergence Society
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• v.8 no.5
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• pp.19-28
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• 2017

In this paper, we propose a method to reduce the difference in image characteristics when multiple camera images are captured for virtual space production. Sixty-four images were used by cross-mounting eight bodies and lenses, respectively. Image analysis compares and analyzes the standard deviation of the histogram and pixel distribution values. As a result of the analysis, it shows different image characteristics depending on the lens or image sensor, though it is a camera of the same model. In this paper, we have adjusted the distribution of the overall brightness value of the image to compensate for this difference. As a result, the average deviation was the maximum of (Indoor: 6.89, outdoor: 24.23), we obtained images with almost no deviation (Indoor: maximum 0.42, outdoor: maximum: 2.73). In the future, we will study and apply more accurate image analysis methods than image brightness distribution.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.12
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• pp.65-84
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• 1999

During the past few decades, we have witnessed three approaches to overcome the legal disparities between trading countries: - determining the individual governing law in accordance with the conflict of laws principle; - unifying and harmonizing private international law into uniform rules and substantive laws under the auspices of ICC, UNCITRAL, UNIDROIT and various NGOs ; and - drafting model laws like the UNCITRAL Model Law on Electronic Commerce and promoting member countries to enact them. Against this backdrop, the United Nations Convention on Contracts for the International Sale of Goods (CISG) and the process by which it was adopted, established the benchmark for the unification of commercial law. The CISG, completed in 1980, merged civil and common law concepts and came into force in 1988 after a certain number of countries endorsed the treaty. Besides the CISG, the U.N. Limitations Convention and the UNIDROIT Principles of International Commercial Law, to name a few, have attempted to set cross-border legal norms and standards in the international business transactions. However, since the advent of computer-based commerce, there have emerged all-out efforts to establish uniform rules before national legal systems have been developed. As a consequence, the Model Law on Electronic Commerce has become a specimen legislation covering functional equivalents of paper-based writing and signature. For the credit enhancement exemplified by the Uniform Rules for Demand Guarantees (ICC Publication No.458), the UNCITRAL prepared the U.N. Convention on Independent Guarantees and Stand-by Letters of Credit, which was adopted by the U.N. General Assembly in 1995 but remains still not effective as only two countries have ratified this treaty so far. In this connection, two draft conventions underway at UNIDROIT and UNCITRAL deserve our attention as the probability of unification in the Korean Peninsula is mounting. They are to create security interests for commercial finance in moveable equipment and accounts receivable. The UCC-type security rights are regarded to be useful to enable the North Koreans with limited properties to borrow from the banks.