• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.739-746
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• 1999

The spectral aerosol optical thickness of vertical air columns were measured by a ground-based multi-channel sunphotometer at the BAPMoN station(36$^{\circ}$31'N, 126$^{\circ}$19'E) in Anmyon Island, Korea, from 1 March 1998 to 31 May 1998. We used the data of three yellow sand and two clear sky days in order to analyze the temporal variations in aerosol optical thickness at the station. The basic aerosol optical thickness generally represented smaller than 0.3 in a clear sky and the range 0.5 to 1.1 in yellow sand. Especially the aerosol optical thickness represented larger than 0.9 in a heavy yellow sand. It was found that the aerosol optical thickness of yellow sand was highly increased in comparison with the case of a clear sky andparticles larger than 0.5$mu extrm{m}$ were also increased in the spectral distribution of aerosol volume during yellow sand. Consequently the spectral variations in tropospheric aerosol caused by yellow sand were determined by the number concentration of particles larger than 0.5${\mu}{\textrm}{m}$ and the magnitude of yellow sand.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.4
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• pp.240-246
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• 2013

In heterogeneous networks, the almost blank subframes (ABS) for inter-cell interference coordination (ICIC), which can be protected from the CCI due to unutilized subframes (i.e., ABS) is proposed. However, the analytical model for ABS-based systems has not been fully studied yet. In this paper, we derive a new analytical model to evaluate the performance of ABS-based systems. In an analytic model, we assume that each carrier in multicarrier systems, such as in OFDMA, is subject to large-scale fading, which is independent of other carriers. As a performance measure, we present the cumulative distribution function (CDF) for the effective SINR. We show the accuracy of the analytical model via simulation results.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.5
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• pp.259-268
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• 2020

This study aims to provide empirical evidence on the causal relationship between bribery and firm innovation. To this end, we use a micro-dataset of small and medium firms in Vietnam surveyed in 2015. Given the binary nature of the dependent variable, a simple probit regression model is employed. However, as bribery variable is potentially endogenous, a simple probit regression may give biased estimates. We deal with the potential endogeneity by making use of the bivariate probit model. A property of the bivariate probit model is that it can produce efficient estimates of a typical probit model with endogenous binary explanatory variable. A Hausman-like likelihood ratio test is implemented following the estimation to test the existence of endogeneity. We find that bribery significantly undermines firm innovation. Also, firms run by household appear less innovative. The probability of innovation diminishes significantly if firm owners or managers have previous experience in firm products. As expected, larger firms seem to be more innovative. Exporters tend to be more innovative compared to non-exporters. Our findings provide support to the hypothesis that bribery is detrimental to firm innovation and, thus, innovation may be a mediating channel, through which, bribery impedes firm long-term performance.

• Asian Journal of Business Environment
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• v.7 no.4
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• pp.27-33
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• 2017

Purpose - The paper aims to explore the critical and uncover issues encountered to the supply-chain companies in launching halal based services in India. Research design, data, and methodology - After a meticulous review of relevant literature on the halal concept and halal logistics, researchers involved in a data collection by conducting semi-structured focus group interviews. Four groups with a maximum of 5 members each have chosen from the areas of transportation, warehousing, certification, and packaging. A total of 20 questionnaires were collected by applying purposive sampling method. Results - More than 95 percent of the chosen focus groups agreed that they know only about halal but don't have any exposure to halal logistics. The discussion has revealed that the adoption rate for halal transportation, warehousing, halal certification, and packaging is almost zero. The respondents were chosen only from transportation, warehousing, certification and packaging companies from south India which are operating throughout India. This research never attempts to be acquainted with the opinions of channel members who directly or indirectly involved in meeting customer demands. Conclusions - This is a ground-breaking effort aimed to study the critical issues related to Indian halal logistics which is beneficial to both logistic companies as well as to the academic world.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.7
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• pp.279-291
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• 2020

This study aims to develop the concept of innovation models with the marketing channel construct approach, marketing innovation, product segmentation, and customer insight; as well as improvements to the theory of resource-based combined with the method of service-dominant logic. This study approach is based on quantitative descriptive conducted with three stages of testing scenarios. The first test is the mapping of the innovation model construct through testing the validity and reliability with the moderation of customer orientation variables. The second scenario examines the relationship of influence between the independent variables on the dependent variable of 29 hypothetical analysis equation modeling. The unit of analysis was conducted on 497 SMEs involved in the food and beverage sectors, with the criteria being SMEs must have a rating of 4-5 points on the Go-Food applications software. The results shown that: 1) the construct used to develop an innovative model both directly and via moderation is positive and significant; 2) Through a complicated relationship that involves all components of the variable, it outlines a positive and significant effect except for the path of analysis (μ5). The theoretical and managerial implications state that the service-dominant logic approach and resource-based view theory have extreme reliability and interrelations.

• Asian Journal of Atmospheric Environment
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• v.11 no.1
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• pp.54-60
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• 2017

Quantifying the trace elements in infinitesimal ambient liquid samples (e.g., single raindrop, cloud/fog water, and the soluble fraction extracted from the particles collected for a short time) is an important task for understanding formation processes, heating/cooling rates, and their health hazards. The purpose of this study is to employ an in-air micro PIXE system for quantitative analysis of the trace elements in a thimbleful of reference liquid sample. The bag type liquid sample holder originally designed with $10{\mu}m$ thick $Mylar^{(R)}$ film retained the original shape without any film perforation and apparent peaks of film blank by the end of the analysis. As one of tasks to be solved, the homogeneity of the elemental distribution in liquid reference species was verified by the X-ray line profiles for several references. It was possible to resolve the significant peaks for whole target elements corresponding to the channel number of micro-PIXE spectrum. The calibration curves for the six target elements (Si, S, Cl, Fe, Ni, and Zn) in standard solutions were successfully plotted by concentration (ppm) and ROI of interest net counts/dose (nC).

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.201-202
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• 1998

In this paper we suggested an automated method for detecting and counting rapid eye movement(REM) using EOG during sleep. This method is formulated by two step fuzzy logic. At first step, the velocity and the distance of single channel eye movement are used for the fuzzy input to get the possibility of being REM at each EOG. At second step, the two possibility values of both EOG from the first step and the correlation coefficient of both eye movements are used for the fuzzy logic input, and the output is the final possibility of being Rapid Eye Movement. We applied this algorithm to the normal and narcoleptic sleep data and compared the difference. We found the possibility that the count of REM can be a parameter that has significant physiological meanings.

• Journal of the korean society of oceanography
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• v.32 no.3
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• pp.120-127
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• 1997

Depositional environment off the Shihwa Dam has been studied to investigate the change of sedimentation process and the pollution. In order to understand how the sediments are distributed, polluted and modified, depositional factors have been analyzed and compared with the previous data. Study area, located off the Shihwa Dam, was surveyed to collect 25 bottom samples and 2 cores in 1996 and echo-sounding in 1997. These sediments were analyzed for the study of the global characteristics of sediment such as grain size and organic matter. Among these samples, the selected twenty surface sediments were analyzed for the comparison with their contents of metallic elements (Al, Mn, Fe, V, Cr, Co, Ni, Cu, Zn, Cd, Pb, As). According to field and lab analysis of sediments, three sedimentological zones have been generally identified around study area; near the dam (sandy Silt), near the dike (Sand) and offshore (silty Sand) zones. Textural parameters show that the content of silt and clay is dominant near the dam excepting the dike zone of LNG Storage Base and offshore (Palmido). The total concentration of Mn, Ni, Fe, Zn and Cd in bulk sediments was increased after the construction of the dam, while the content of Mn and Cr were higher near tidal channel than in the offshore area. Meanwhile, the annual increasing pattern of some heavy metal has appeared in this area. Based on this primary study, modification of the depositional environment may be caused by the construction of the dam and LNG Storage Base. Additionally, environmental evaluation on organic/inorganic factors has been suggested for interpreting environmental changes caused by coastal development in the nearshore such as the Shihwa coastal area.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3414-3434
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• 2016

Classical key generation is complicated to update and key distribution generally requires fixed infrastructures. In order to eliminate these restrictions researchers have focused much attention on physical-layer (PHY-layer) based key generation methods. In this paper, we present a PHY-layer fingerprints based fuzzy key generation scheme, which works to prevent primary user emulation (PUE) attacks and spectrum sensing data falsification (SSDF) attacks, with multi-node collaborative defense strategies. We also propose two algorithms, the EA algorithm and the TA algorithm, to defend against eavesdropping attacks and tampering attacks in mobile cognitive radio networks (CRNs). We give security analyses of these algorithms in both the spatial and temporal domains, and prove the upper bound of the entropy loss in theory. We present a simulation result based on a MIMO-OFDM communication system which shows that the channel response characteristics received by legitimates tend to be consistent and phase characteristics are much more robust for key generation in mobile CRNs. In addition, NIST statistical tests show that the generated key in our proposed approach is secure and reliable.

• Proceedings of the KOR-KST Conference
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• 1998.10a
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• pp.479-487
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• 1998

현재 도로화물운송을 분석하는데 가장 많이 사용되는 지표는 수송톤(ton)과 톤-키로(ton-km)이다. 하지만 이러한 두 지표는 도로화물운송체계를 설명하기보다는 단순히 운송실적을 나타내는 통계지표이다. 따라서 본 연구에서는 한국의 도로화물운송체계를 설명할 수 있는 운송단계, 총 운송거리, 순물동량, 평균운송거리 등의 4개 요소를 추정하였다. 그리고 한국의 도로화물 운송체계의 문제점을 진단하기 위하여 외국이 도로화물운송체계와 비교분석하였다. 본 연구에서 발견된 주요결과는 (1) 한국과 대만은 운송단계와 총 운송거리가 증가하고 평균운송거리는 감소하는 추세를 보였고, (2) 한국과는 대조적으로, 미국, 일본, 네덜란드는 운송단계와 총 운송거리는 감소하고 평균운송거리는 증가하는 변화추세를 보였으며, (3) 시계열 분석결과, 운송단계의 증가는 GDP대비 물류비와 운송비를 증가시키고 운송단계의 감소는 GDP대비 물류비와 운송비를 감소시키는 것으로 나타났다. 본 연구결과, 한국의 도로화물운송체계는 운송단계를 증가시키는 비효율적인 방향으로 진행되어왔고 이러한 운송단계의 증가는 GDP대비 물류비를 증가시키는 주요 원인임을 알 수 있었다. 따라서 한국의 도로화물운송체계를 개선시키기 위해서는 지능형 화물운송체계의 구축, 복합기능의 화물거점시설 확충, 화물자동차 운송업의 규제완화, 기업물류관리의 선진화 등의 정책을 통하여 불필요한 운송단계의 단축이 필요하다.