• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.2
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• pp.99-108
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• 2020

In the field of aircraft icing prediction, surface roughness has been considered as critical factor because it enhances convective heat transfer and changes local collection efficiency. For this significance, experimental studies have been conducted to acquire the quantitative data of the formation process. Meanwhile, these experiments was conducted under low-speed condition due to the measurement difficulties. However, it has not been investigated that how the flow characteristic of low-speed will effects to the surface roughness. Therefore, the present study conducted experiment under low-speed icing condition, and analyzed the relation between surface roughness characteristics and icing condition. As an analysis method, the dominant parameters used in the previous high-speed experiments are employed, and roughness characteristics are compared. The size of roughness element was consistent with the previous known tendency, but not the smooth zone width.

• Molecules and Cells
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• v.37 no.7
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• pp.554-561
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• 2014

Lysophosphatidic acid (LPA) is a lipid growth factor that exerts diverse biological effects through its cognate receptors ($LPA_1-LPA_6$). $LPA_1$, which is predominantly expressed in the brain, plays a pivotal role in brain development. However, the role of $LPA_1$ in neuronal migration has not yet been fully elucidated. Here, we delivered $LPA_1$ to mouse cerebral cortex using in utero electroporation. We demonstrated that neuronal migration in the cerebral cortex was not affected by the overexpression of $LPA_1$. Moreover, these results can be applied to the identification of the localization of $LPA_1$. The subcellular localization of $LPA_1$ was endogenously present in the perinuclear area, and overexpressed $LPA_1$ was located in the plasma membrane. Furthermore, $LPA_1$ in developing mouse cerebral cortex was mainly expressed in the ventricular zone and the cortical plate. In summary, the overexpression of $LPA_1$ did not affect neuronal migration, and the protein expression of $LPA_1$ was mainly located in the ventricular zone and cortical plate within the developing mouse cerebral cortex. These studies have provided information on the role of $LPA_1$ in brain development and on the technical advantages of in utero electroporation.

• Information Systems Review
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• v.8 no.3
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• pp.175-200
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• 2006

Application service provider(ASP) model is emerging as a new form of application outsourcing. ASP model may be attractive for small companies and even some medium-sized companies because these companies lack appropriate resources and technical expertise to develop and operate their information system. However, studies of ASP model have so far been neglected. Service quality is argued to be a crucial success factor for ASP, but yet there is not an empirically validated instrument for measuring ASP service quality. Therefore, this paper aims to develop and test a model for measuring ASP service quality. In order to accomplish these, SERVQUAL that has developed in marketing area were adapted to the context of this study. The research sample was designed by randomly selecting 300 different companies from the database that listed up the small companies participating in "ASP based e-business project for small enterprises". 240 usable responses were received by interview. The results are that reliability and tangibility impact user performances and satisfaction more than any of the service quality dimensions.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1075-1080
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• 2014

This study aims at dedicating to relevant technology fields by suggesting design methods of structures and estimating their safety in relation to substructure for offshore wind power requiring high safety to various environment conditions. Especially, with respect to 5MW Offshore Wind Power System, this study will provide information about major wind directions and duration in combination with the developing wave climate at the test field. Therefore, connections between wind fields and approaching wave trains will be estimated and their intensity, direction and time shift will be pointed out. Furthermore, the local pressure distribution of breaking waves will be investigated by physical and numerical modeling. The currently applied structural and fatigue assessment of support structures for offshore wind energy converters is based on common design rules. Normally, constructions in structural engineering are treated as limited, single structures. This means that varying aspects of manufacturing are considered by high safety factors.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.31-34
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• 2016

System In Package (SiP) is getting popular and momentum for the recent wearable, IoT and connectivity application apart from mobile phone. This is driven by market demands of cost competitive, lighter and smaller/thinner and higher performance. As one of many semiconducting assembly products, Leadframe product has been widely used for low cost solution, light/ small and thin form factor. But It has not been applied for SiP although Leadframe product has many advantages in cost, size and reliability performance. SiP is mostly based on laminate substrate and technically difficult on Leadframe substrate because of a limitation in SMT performance. In this paper, Leadframe based SiP product has been evaluated about key technical challenges in SMT performance and electrical shield technology. Mostly Leadframe is considered not available to apply EMI shield because of tie-bar around package edge. In order to overcome two major challenges, connection bars were deployed properly for SMT pad to pad and additional back-side etching was implemented after molding process to achieve electrical isolation from outer shield coating. This product was confirmed assembly workability as well as reliability.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.179-182
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• 2001

The chloride volatilization method for the recovery of zirconium and removal of uranium from zirconium containing metallic wastes formed in spent fuel reprocessing was studied using the simulated alloy waste, i.e. the mixture of Zr foil and UO$_2$/U$_3$O$_{8}$ powder. When the simulated waste was heated to react with chlorine gas at 350- l00$0^{\circ}C$, the zirconium metal changed to volatile ZrCl$_4$showing high volatility ratio (Vzr) of 99%. The amount of volatilized uranium increases at higher temperatures causing lowering of decontamination factor (DF) of uranium. This is thought to be caused by the chlorination of UO$_2$ with ZrCl$_4$vapor. The highest DF value of 12.5 was obtained when the reaction temperature was 35$0^{\circ}C$. Addition of 10 vol.% oxygen gas into chlorine gas was effective for suppressing the volatilization of uranium, while the volatilization ratio of zirconium was decreased to 68% with the addition of 20 vol.% oxygen. In the case of the mixture of Zr foil and U$_3$O$_{8}$, the V value of uranium showed minimum (44%) at 40$0^{\circ}C$ with chlorine gas giving the highest DF value 24.3. When the 10 vol.% oxygen was added to chlorine gas, the V value of zirconium decreased to 82% at $600^{\circ}C$, but almost all the uranium volatilized (Vu=99%), which may be caused by the formation of volatile uranium chlorides under oxidative atmosphere.ere.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.309-318
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• 2004

This research automatically designed psc-box girder bridges by using an optimum design program and applied the results to the various types of bridges to verify if common facts used in steel bridges or concrete bridges can be applied to PSC bridges. Namely, it investigated appropriate unequal span length division by comparing with bridge of unequal and equal span length division, and verified the influence of the load factors which are changed by time or specification applying the results to various types of bridge. and it applied reinforced concrete bridge and steel bridge's variable girder depth which is slender and effective to save material costs to PSC box girder bridges. Technical solution of optimum design program used SUMT procedure, and Kavlie's extended penalty function to allow infeasible design points in the process. Powell's direct method was used for searching design points and a gradient's approximate method was used to reduce the design time.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.435-443
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• 2015

Offshore structure may be considerably vulnerable to fatigue failure while initial flaw propagates under cyclic loading, so crack propagation analysis/fracture/yield assessments about initial flaw detected by NDT are necessarily required. In this paper, case studies have been conducted by flaw assessment program using engineering criticality analysis (ECA) approach. Variables such as flaw geometry, flaw size, structure geometry, dynamic stress, static stress, toughness, crack growth rate, stress concentration factor (SCF) affected by weld are considered as analysis conditions. As a result, the safety of structure was examined during fatigue loading life. Also, critical initial flaw size was calculated by sensitivity module in the developed program. The flaw assessments analysis using ECA approach can be very useful in offshore industries owing to the increasing demand on the engineering criticality analysis of potential initial flaws.

• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.131-138
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• 2020

Malware is generally recognized as a computer program that penetrates another computer system and causes malicious behavior intended by the developer. In cyberspace, it is also used as a cyber weapon to attack adversary. The most important factor that a malware must have as a cyber weapon is that it must achieve its intended purpose before being detected by the other's detection system. It requires a lot of time and expertise to create a single malware to avoid the other's detection system. We propose the framework that automatically generates variant malware when a binary code type malware is input using the DCM technique. In this framework, the sample malware was automatically converted into variant malware, and it was confirmed that this variant malware was not detected in the signature-based malware detection system.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.1
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• pp.99-112
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• 1997

A quantitative fit test, condensation nuclei counting(Portacount 8025, TSI), was performed concurrently with a qualitative fit test, sodium saccharin(FT-10, 3M) to evaluate FF values and to determine the correlation between two methods. Two brands of full facepieces, T, S and two brands of half masks, T, S, were fit tested, respectively, on 103 wearers one time. The FF values obtained by CNC QNFT were lognormally distributed. The FF values for T brand of respirators were statistically very much higher than those for S brand of respirators. For a full facepiece wearer combination having a $FF{\leq}100$, as determined by CNC QNFT, the point estimate of the probability of that combination not being rejected by the saccharin QLFT was found to be 0.09 with 90% confidence that this statistic is not expected to exceed 0.25. For a half mask wearer combination having a $FF{\leq}10$, as determined by CNC QNFT, the point estimate of the probability of that combination not being rejected by the saccharin QLFT was found to be 0.10 with 90%, confidence that this statistic is not expected to exceed 0.23. The uncertainty associated with each estimate, however, is large due to the small number of study subjects with inadequately fitting respirators. This result indicates that saccharin QLFT may be more suitable for adequately fitting respirators than inadequately fitting respirators.