• Journal of Science and Technology Studies
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• v.1 no.1 s.1
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• pp.201-234
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• 2001

Sociology(or social science in general) is often diagnosed as in the state of 'crisis' after the collapse of socialism and the erosion of national societies because of rapid globalization. This paper introduces some recent work within science and technology studies(STS) and discusses its potentials to reinvigorate sociology. Although sociologists have rarely regarded STS as contributing to 'mainstream' issues in sociology, an increasing number of STS writers and sociologists have recently started to notice such possibilities. One main reason of this recent change is that STS is no longer merely concerned to convey substantive findings about science and technology, but instead attempts to reconstruct key notions of sociology such as 'social', 'society' and 'agency'. It is in this respect that the discussion below aims to introduce, discuss, and assess the potential contribution of some recent work of STS to sociology. In particular, it is 'actor-network theory'(ANT) that explicitly attempts to examine and suggest the ways in which STS ran help innovate sociology. One major characteristics of ANT is to impute 'agency' to things(nonhumans) unlike traditional sociology. ANT argues that if sociology studies heterogeneous relationships between humans and nonhumans instead of human relations only, it can become once again a vigorous discipline which is able to provide alternative worlds central to the basis of sociology. So this paper focuses on, not the diverse approaches of STS, the characteristics of ANT and its potential contribution to sociology. The author concludes that ANT can not only rejuvenate sociology by implicating new forms of alternative worlds but also open the possibility to contribute to the democratic reformulation of human-nonhuman relationships.

• Knowledge Management Research
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• v.22 no.1
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• pp.39-56
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• 2021

In the current knowledge society, mobile devices have become a useful tool for performing work. In the context of COVID-19 which has made digital transformation inevitable, the importance of mobile work behaviors - performing work tasks through mobile devices - is further highlighted. Drawing from the behavioral immune system theory and cognitive appraisal theory of emotions, this study proposes that individual workers' concern about getting infected by COVID-19 will be negatively related to job satisfaction but positively related to mobile work behaviors. We further propose that leaders' communality and agency trait will be positively related to both job satisfaction and the increase of mobile work behaviors. Analyses of a matched dataset comprising survey data and mobile application usage data from 407 workers showed that their leaders' agency and communality were significantly related to the workers' job satisfaction. However, their mobile productivity was significantly related only to the communality of their leaders. The results of this study will provide useful theoretical and practical implications for researchers and managers who aim to understand and promote the technology adoption and knowledge productivity of workers in a pandemic situation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.1-1
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• 2005

Japan Aerospace Exploration Agency(JAXA) has been conducting research and development of the Scramjet engines and their derivative combined cycle engines as hypersonic propulsion system for space access. Its history will be introduced first, and its recent advances, focusing on the engine performance progress, will follow. Finally, future plans for a flight test of scramjet and ground test of combined cycle engine will be introduced. Two types of test facilities for testing those hypersonic engines. namely, the 'Ramjet Engine Test Facility (RJTF)' and the 'High Enthalpy Shock Tunnel (HIEST)' were designed and fabricated during 1988 through 1996. These facilities can test engines under simulated flight Mach numbers up to 8 for the former, whereas beyond 8 for the latter, respectively. Several types of hydrogen-fueled scramjet engines have been designed, fabricated and tested under flight conditions of Mach 4, 6 and 8 in the RJTF since 1996. Initial test results showed that the thrust was insufficient because of occurrence of flow separation caused by combustion in the engines. These difficulty was later eliminated by boundary-layer bleeding and staged fuel injection. Their results were compared with theory to quantify achieved engine performances. The performances with regards to combustion, net thrust are discussed. We have reached the stage where positive net thrust can be attained for all the test coditions. Results of these engine tests will be discussed. We are also intensively attempting the improvement of thrust performance at high speed condition of Mach 8 to 15 in High Enthalpy Shock Tunnel (HIEST). Critical issues for this purposemay be air/fuel mixing enhancement, and temperature control of combustion gas to avoid thermal dissociation. To overcome these issues we developed the Hypermixier engine which applies stream-wise vortices for mixing enhancement, and the M12-engines which optimizes combustor entrance temperature. Moreover, we are going to conduct the flight experiment of the Hypermixer engine by utilizing flight test infrastructure (HyShot) provided by the University of Queensland in fall of 2005 for comparison with the HIEST result. The plan of the flight experiment is also presented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1272-1280
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• 2008

In this paper, we have proposed a phase noise model of fast frequency hopping synthesizer with DDS Driven PLL architecture. To accurately model the phase noise contribution of noise sources in frequency hopping synthesizer, they were investigated using model of digital divider for PLL, DAC for DDS and Leeson's model for reference oscillator and VCO. Especially it was proposed that the noise component of low pass filter was considered together with the phase noise of VCO. Under assuming linear operation of a phase locked loop, the phase noise transfer functions from noise sources to the output of synthesizer was analyzed by superposition theory. The proposed phase noise prediction model was evaluated and its results were compared with measured data.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.268-274
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• 2013

In this paper, objective functions are defined for optimization of radar absorbing structures (RAS) on the aircraft wing leading edge. RAS is regarded as a single layer structure made of dielectrics. Design variables are the real and imaginary parts of complex permittivity. Reflection coefficient(RC) and radar cross section(RCS) are used in the objective function respectively. Transmission line theory is employed to calculate the RC. The RCS is evaluated by using physical optics(PO) for a leading edge part model. Genetic algorithm(GA) is used to perform optimization procedures. The radar absorbing performance of designed RAS is assessed by the RCS of a wing which has RAS on the leading edge.

• Journal of the Korean Ceramic Society
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• v.38 no.3
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• pp.207-211
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• 2001

The effects of the sintering atmosphere and Ni content on t도 densification of TiB$_2$-Ni have been investigated. TiB$_2$powder compacts containing 10, 20, and 30 wt% Ni were liquid-phase sintered at 1500-1$700^{\circ}C$ in vacuum or in flowing Ar. The densification was enhanced as Ni content increased. For a given Ni content, the densification was faster in compacts in compacts with larger grain size. These densification behaviors agree well with the prediction of the recently developed pore-filling theory. For samples containing high Ni contents, 80TiB$_2$-20Ni and 70TiB$_2$-30Ni, the densification was faster in vacuum than in Ar. In particular, 70TiB$_2$-30Ni was fully densified at 1$700^{\circ}C$ for 60min in vacuum. The suppressed densification in Ar was due to the entrapped Ar in the isolated pores. On the other hand, for 90TiB$_2$-10Ni, the Ar-sintering resulted in higher densification than did the vacuum-sintering. This result was attributed to the suppression of Ni volatilization by the Ar in the furnace and a retarded isolation of pores due to the limited amount of liquid in the sample. Therefore, vacuum sintering is recommended for the preparation of TiB$_2$-Ni with a high Ni content while Ar sintering is recommended for the preparation of TiB$_2$-Ni with a low Ni content.

• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.1
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• pp.19-28
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• 1996

This study has investigated the optimization of NDT method and the minimum detectable defect size for complex structures such as the solid propellant rocket motor using real time X-ray imaging system. Test specimens were made of steel plates with various defect size, and installed with proper thickness for which solid propellant, rubber, and case converted to the steel equivalent thickness according to the radiographic equivalent theory. As the results, this examination obtained optimum magnification and X-ray energy, dose rate according to steel equivalent thickness, also, obtained the relationship between minimum detectable defect size and the ratio(defect depot/object thickness). Thus, this simulated test is the preliminary procedure before performing NDT for real objects, and is possibly applied for NDT of other complex structures.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.118-125
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• 2015

According to the children's crime risk is increased, national police agency has implemented child safety keeper system since 2009. Despite the importance of child safety keeper studies, there was no seeking of empirical research and development plan for the operation. The purpose of the study is to find ways to improve the effectiveness of the child safety keeper system. To achieve the research objectives, all the child safety keepers were surveyed by quota sampling in the 16 provincial police agency. Questionnaire analyzed by frequency analysis, t-test, Avova, multiple regression analysis. The result of analysis is the need to strengthen links with child safety keeping house, participatory setting for the patrol route, the improvement of education management and supervision, adequacy of allowance, strengthening contact with children for job success awareness.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.175-182
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• 2016

In the 21st century knowledge and information society, Electronic Contracts made with the intention of electronic computer information networks are emerging as a new legal problem which can not be solved in the conventional legal system governing contracts. In other words, the indicator's decision determines the effect and formation of the contracts in the face-to-face or written contracts but electronic decision through computer information network is established the working process of electronic signals-electronic contracts are not only difficult to separate the decision-making process but questioned to be solved by the theory of the general legal action. Ministry of Transportation is scheduled to introduce real estate sales and lease contract using a variety of electronic devices such as computer, tablet PC, smart phones and so on without a paper contract. This system is conducted to global expansion of Seoul in demonstration zone on May 8, 2016 and will be implemented nationwide in the second half of 2017. Electronics contract Real estate has some benefits because made by linking electronic contract system and the electronic registration system - the economic effects discounts on various kinds of fees, the prevention from real estate fraud beforehand and the solution to the complexity of the process the seller and the buyer visits The Real estate agency. However, it has some problem- the disorder in the real estate contract market, the occurrence of the real estate agency accident and the author of the electronic real estate contracts have limited only to realtor. In this paper, I suggest the activation plan to search for establishment and effect of electronic contracts and declaration of intention in electronic depending on the Electronic Contract Real Estate system.

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.743-756
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• 2009

This paper tries to analyze how the governance institutions of the Port Authority of New York and New Jersey overcome agent problems in public agencies based on the Principal-Agent Theory, and find the implications that will be helpful to the governance of port authorities in Korea. The Port Authority's governance is characterized by decentralization of personnel rights, open meetings policy, freedom of information policy, public hearings, and fiscally self-supporting system. Those characteristics are helpful in overcoming the agent problems of public agency, such as adverse selection, moral hazard, and complicated external structure, through reinforcing of monitoring agent by principal, easing of information asymmetry between principal and agent, and clarification of organizational ownership structure. Those characteristics may give many implications for the design of governance structures of port authorities in Korea.