• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.289-292
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• 2008

Highly over-expanded nozzle of the rocket engines will be excited by non-axial forces due to flow separation at sea level operations. Since rocket engines are designed to produce axial thrust to power the vehicle, non-axial static and/or dynamic forces are not desirable. Several engine failures were attributed to the side loads. Present work investigate the unsteady flow in an over-expanded rocket nozzle in order to estimate side load during a shutdown/starting. Numerical computations has been carried out with density based solver on multi-block structured grid. Present solver is explicit in time and unsteady time step is calculated using dual time step approach. AUSMDV is considered as a numerical scheme for the flux calculations. One equation Spalart-Allmaras turbulence model is selected. Results presented here is for two nozzle pressure ratio i.e. 100 and 20. At 100 NPR, restricted shock separation (RSS) pattern is observed while, 20 NPR shows free shock separation (FSS) pattern. Side load is observed during the transition of separation pattern at different NPR.

• Knowledge Management Research
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• v.22 no.1
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• pp.85-103
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• 2021

While there is a rapid transition to smart work due to COVID-19, not many studies have measured the changes in organizational culture after firm-wide institutionalization of smart work. Through a questionnaire and a series of stakeholder interviews, this study examined how and to what extent employees' perception of organizational culture changed after the introduction of smart work in a large leisure service company H in South Korea. The working culture of the organization is measured as the changes in the organizational members' perception on seven dimensions: strategic innovativeness, organizational flexibility, fair human resource management, rational decision making processes, organizational vitality, trustful collaboration, proactive leadership. The results demonstrated that, after the introduction of smart work, the organizational members' perception on strategic innovativeness, organizational flexibility, organizational vitality, trustful collaboration have declined significantly while the changes in fair human resource management, rational decision making processes, and proactive leadership are insignificant. Though found to be insignificant, follow up interviews revealed that participants think that the role of management leadership is very critical for the smart work systems to be institutionalized successfully. While the smart work may have different effects depending upon industry or organizational characteristics, this study present a case for changes in organizational culture after institutionalizing smart work. Implications are discussed with further research issues at the end.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.8
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• pp.22-34
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• 1999

In this paper, an efficient test algorithm for embedded dual-port memories is presented. The proposed test algorithm can be used to test embedded dual-port memories faster than the conventional multi-port test algorithms and can be used to completely detect stuck-at faults, transition faults and coupling faults which are major target faults in embedded memories. Also, in this work, BIST which performs the proposed memory testing algorithm is designed using Verilog-HDL, and simulation and synthesis for BIST are performed using Cadence Verilog-XL and Synopsys Design-Analyzer. It has been shown that the proposed test algorithm has high efficiency through experiments on various size of embedded memories.

• Carbon letters
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• v.28
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• pp.55-59
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• 2018

Transition-metal-embedded carbon nanotubes (CNTs) have been accepted as a novel type of sensing material due to the combined advantage of the transition metal, which possesses good catalytic behavior for gas interaction, and CNTs, with large effective surface areas that present good adsorption ability towards gas molecules. In this work, we simulate the adsorption of $O_2$ and $O_3$ onto Rh-doped CNT in an effort to understand the adsorbing behavior of such a surface. Results indicate that the proposed material presents good adsorbing ability and capacities for these two gases, especially $O_3$ molecules, as a result of the relatively large conductivity changes. The frontier molecular orbital theory reveals that the conductivity of Rh-CNT would undergo a decrease after the adsorption of two such oxidizing gases due to the lower electron activity and density of this media. Our calculations are meaningful as they can supply experimentalists with potential sensing material prospects with which to exploit chemical sensors.

• Journal of Mechanical Science and Technology
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• v.17 no.5
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• pp.718-725
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• 2003

The present study addresses the distortion of the compression wave reflected from an open end of a shock tube. An experiment is carried out using the simple shock tube with an open end Computational work is also performed to represent the experimented flows. The second-order Total Variation Diminishing scheme is employed to numerically solve the unsteady, axisy-mmetric, inviscid, compressible governing equations. Both the experimented and predicted results are in good agreement. The generation and development mechanisms of the compression wave, which Is reflected from the open end of the shock tube, are obtained in detail from the present computations. The effect of size of the baffle plate at the open-end that causes the reflection of the incident expansion wave is found negligible. A good correlation is obtained for transition of the reflected compression wave to a shock wave inside the tube. The present data show that for a given wave length of the incident expansion wave the transition of the reflected compression wave to a shock wave can be predicted with good accuracy.

• Information Systems Review
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• v.23 no.4
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• pp.23-43
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• 2021

Due to the recent transition to a non-face-to-face society, many organizations are quickly adapting to foster a smart work environment. The introduction of smart work does not simply end with incorporating ICT systems or solutions into business models since fundamental factors such as forms of employment and work styles need to be in line with the progression of technological advances. However, previous studies regarding smart work focus on improvements in productivity and efficiency from a technology acceptance perspective. Therefore, there is a lack of discussion on innovation resistance from employees and management control when ICT systems are introduced into the workplace. This study empirically analyzes the moderating effects of the organizational control method for employees and innovation resistance within a smart work environment. Additionally, this study aims to identify the structural characteristics that employees resist from an innovation resistance perspective when organizational innovation occurs. The empirical analysis of this study suggests that when smart work such as ICT technology is introduced into the workplace the level of innovation resistance decreases when there is a high level of relative advantage and self-efficacy, whereas the level of innovation resistance increases when there is a high level of use complexity. Moreover, this study revealed that the level of innovation resistance increases when the employees' behaviors were controlled. The results of this study intend to contribute to improving business management by suggesting factors worth considering when incorporating smart work into work places through a thorough case analysis.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.726-730
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• 2013

Complexes synthesized by reacting alkyl and aryl phosphines with different transition metals are of great interest due to their catalytic properties. Many of the phosphine complexes are soluble in polar solvents as a result they find applications in homogeneous catalysis. In our present work we report, four transition metal complexes of Ni(II), Pd(II), Pt(II) and Ru(II) with an asymmetrical ditertiaryphosphine ligand. The synthesized ligand bears a less electronegative substituent such as methyl group on the aromatic nucleus hence makes it a strong ${\sigma}$-donor to form stable complexes and thus could effectively used in catalytic reactions. The complexes have been completely characterized by elemental analyses, FTIR, $^1HNMR$, $^{31}PNMR$ and FAB Mass Spectrometry methods. Based on the spectroscopic evidences it has been confirmed that Ni(II), Pd(II) and Pt(II) complexes with the ditertiaryphosphine ligand showed cis whereas the Ru(II) complex showed trans geometry in their molecular structure.

• Fashion & Textile Research Journal
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• v.11 no.2
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• pp.231-241
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• 2009

Embroidery is one of the oldest methods of textiles surface decoration. The masterpiece "Tapisserie de Bayeux," is one of the earliest Medieval embroideries. Embroidery was popular on a broad scale with introduction of what was called Opus Anglicanum("English work") in the 13th century. France had been producing sophisticated embroideries since the 16th century. England was the country producing the greatest quantity of embroideries of the best quality in the 17th century. Until the 17th century, the Church was the most important patron of needlework. Then a shift in emphasis occurred towards the domestic embroidery. English 17th century domestic embroidery reached a high point of technical brilliance and charm. In France, embroidery was produced on hangings as well as costume. 18th century interest in embellishing the domestic environment, embroideries became much more finely detailed than those of the 17th century with the use of finer wool and silk threads. French silk were the finest in the world, and their embroidery was arguably equally fine both in furnishing textiles and on costumes. "Art Needlework" was the major movement in embroidery in the late 19th century. The Royal School of Needlework was founded in 1872, followed by similar institutions around Britan. Splendid fashion embroidery of French haut-couture that was represented to Lesage atelier in 20th century.

• Journal of computational fluids engineering
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• v.17 no.3
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• pp.53-58
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• 2012

Steady flow simulations through a high pressure turbine guide vanes were carried out. The main objective of the present work is to study the performance of turbulence models on the steady flow prediction from aerodynamic and aerothermal points of view. Three turbulence models were compared, namely SST, k-${\omega}$ and ${\omega}$-Reynolds stress models. The laminar results were also compared. The comparison was done with emphasis on the isentropic Mach number and heat transfer coefficient along the blade, and total pressure loss in the wake region. The calculated isentropic Mach number showed reasonable agreement with experimental data along the blade surface for all three turbulent models. For the total pressure loss in the wake region, ${\omega}$-Reynolds stress model showed the best agreement with the experimental data. However, unless using an appropriate transition model, the heat transfer coefficients of all three turbulent models showed poor agreement with experimental data.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.493-493
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• 2000

Multi-valued decision making for transitional stochastic events was newly derived based on conditional probability of database. The two values (on-off) decision making method without transition had been proposed by one of the author in a previous work for a purpose of realizing human on-off decision making. The current method is an extension of the previous on-off decision making. By combining the conditional probability and the transitional probability, the closed form of the algorithm for the multi-valued transitional decision making was derived. The proposed multi-valued decision making was successfully applied to the determination of the five levels of the vigilance of a subject during the EEG recording; awake stage, drowsy stage and sleeping stages (stage 1, stage 2/3, REM (rapid eye movement)). The method for determining the vigilance level can be directly usable for the two purposes; selection of awake EEG segments for automatic EEG interpretation, and determination of sleep stages through sleep EEG. The proposed multi-valued decision making with a mathematical background of the probability can be applicable widely, in industries and in medical fields for purposes of the multi-valued decision making.