• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.145-156
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• 2021

The research purpose of this paper is to empirically examine the effects of technological readiness and innovation on logistics performance. To build up and maintain an important role in global supply chains, nowadays it is obvious that countries and logistics providers need to achieve competitive advantage in terms of digitalization. However, there is a lack of empirical studies about the impacts of information technologies and innovation potential on the logistics efficiency of countries. Hence, the study analyzes whether the corresponding pillars of the Global Competitiveness Index (GCI) matter for the Logistics Performance Index (LPI) and its dimensions. For determining the effects, the pooled regression approach is applied. The results show that technological readiness and innovation are positively and statistically significantly correlated with logistics performance: competence and quality of logistics services, efficiency of customs clearance processes, ability to track and trace consignments, frequency with which shipments reach consignee within scheduled or expected time, and ease of arranging competitively priced shipments. The findings of this study suggest that investments in innovations and technology progress improve countries' logistics efficiency, which is an important prerequisite for enabling Logistics 4.0 and thus, Industry 4.0 and the digital transformation of the economy and society.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.467-467
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• 2021

기존 저수지 농업용수는 주로 논의 벼재배 용수공급을 목적으로 설계되었지만, 논 지역 타작물 재배 지원 등의 정책으로 논에서 밭으로 전작화가 증가함에 따라 농업용수의 효율적 분배를 위한 논의 전작화 패턴 분석이 필요한 실정이다. 이에 본 연구에서는 공공데이터 포털의 2019년 팜맵을 활용하여 최신 경지 현황을 파악하고, 환경부의 2007년, 2019년 토지피복지도를 이용하여 전작화 패턴을 분석하였다. 구축된 팜맵과 토지피복지도는 환경부 토지피복분류 기준 농업지역 중분류로 일치시켜 분석에 활용되었다. 논, 밭, 시설재배지 등의 농경지 이용 현황 및 전작화 추이는 전국 단위, 권역 단위로 분석되었고, 주요 시도와의 공간적 거리를 전작화 영향인자로 설정하여 DUP(Degree of Urban Proximity) 등의 지표로 그 영향을 확인하였다. 또한, 전체 경지 중 논, 밭의 면적과 증감 추이를 ACR(Area Change Rate) 등의 지표로 전작화 규모를 파악하였고, LPI(Largest Patch Index), LSI(Landscape Shape Index) 등의 지표로 개별/집단화 전작의 패턴분석을 수행하였다. 본 연구로 제시된 저수지 수혜 구역별 논의 전작화 패턴은 논 벼재배와 농업용수 수요 특성이 상이한 밭작물에 안정적 용수공급 체계 구축 등의 기초자료로 활용 가능할 것으로 생각된다.

• The Journal of the Acoustical Society of Korea
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• v.31 no.7
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• pp.441-448
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• 2012

Spread spectrum provides the minimized inter-symbol interference, the low probability of intercept and the multiple access capability. This paper presents a direct sequence spread spectrum with carrier/timing recovery and equalizer which compensates the delay spread caused by multipath transmission. When the sea trials were performed in Korean East Sea, the bit error rates of QPSK and direct sequence spread spectrum are $1.46{\times}10^{-2}$ and $5.17{\times}10^{-4}$ at 3 km source-receiver range, respectively.

• Journal of electromagnetic engineering and science
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• v.9 no.3
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• pp.130-140
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• 2009

The design theory and experimental results of a true random noise radar system are presented in this paper. Target range information can be extracted precisely by correlation processing between the delayed reference and the signal received from a target, and the velocity information by the Doppler processing with successive correlation data. A K-band noise radar system was designed using random FM noise signal, and the characteristics of the fabricated system were examined with laboratory and outdoor experiments. A C-band random FM noise signal was generated by applying a low-frequency white Gaussian noise source to VCO(Voltage Controlled Oscillator), and a K-band Tx noise signal with 100 MHz bandwidth was obtained by using a following frequency multiplier. Two modified wave-guide horn arrays were designed and fabricated, and used for the Tx and Rx antennas. The required amount of Tx/Rx isolation was attained by using a coupling cancellation circuit as well as keeping them apart with predetermined spacing. A double down-conversion scheme was used in the Rx and reference channels, respectively, for easy post processing such as correlation and Doppler processing. The implemented noise radar performance was examined with a moving bicycle and a very high-speed target with a velocity of 150 m/s. The results extracted by the Matlab simulation using the logging data were found to be in a reasonable agreement with the expected results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2187-2193
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• 2010

A specific radar system can be implemented more easily using the frequency modulated continuous wave comparing with the pulse Doppler radar. It also has the advantage of LPI (low probability of interception) because of the low power and wide bandwidth characteristics. These radars are usually used to cover the short range area and to obtain the high resolution measurements of the target range and velocity information. The transmitted waveform is used in the mixer to demodulate the received echo signal and the resulting beat signal can be obtained. This beat signal is analyzed using the FFT method for the purpose of clutter removal, detection of a target, extraction of velocity and range information, etc. However, for the case of short signal acquisition time, this FFT method can cause the serious leakage effect which disables the detection of weaker echo signals masked by strong side lobes of the clutter. Therefore, in this paper, the weighting window method is analyzed to suppress the strong side lobes while maintaining the proper main lobe width. Also, the results of FFT beat spectrum analysis are shown under various environments.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.13-24
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• 2018

As food consumption pattern changes (reduced rice consumption and increased consumption of fresh vegetables), managing upland fields became a greater priority. However, the agricultural infrastructure projects have been focused on rice farming, and the infrastructure level to support dry fields cultivation is insufficient. The purpose of this study was to spatial distribution analysis of these dry fields with farm manager registration information. Using FRAGSTATS, we analyzed landscape indices (TA/CA, NP, PD, LSI, LPI, PLADJ, COHESION, CONNECT, AI) of farmlands in which farmers in 13 regions (Si or Gun) cultivated dry-field crops. As results of this analysis, the total area of the fields in Naju-si, Hampyeong-gun and Suncheon-si were found to be wider, but the average area of a patch in Youngam-gun, Hampyeong-gun and Jangseong-gun were wider than other regions. On average, each farmer had farmlands containing of 1.7~2.4 patches and cultivated crops in fields of 0.2~0.5 ha. Farmlands of Hampyeong-gun, Youngam-gun, Naju-si showed high values in adjacency indices, however the farmlands of Suncheon and Gwangyang showed fragmented distribution with low values in adjacency indices. These results of fragmentation analysis of farmlands could be used when we establish the plan of an agricultural infrastructure project or select places for a collaborative agricultural management business promotion project.

• Journal of the Economic Geographical Society of Korea
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• v.12 no.1
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• pp.1-18
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• 2009

The aim of this study is to analyze the characteristics of firms related to products for the elderly. The data are based on statistics, questionnaire surveys and interviews with the persons related to the industry. Firms are classified into $3\times3$ matrix with the indexes of innovation performance and network participation. The former is measured with the number of patents and the latter is evaluated by the degree centrality of firms' network in the industries. Combining the previous indexes with other properties, the 9 categories are merged into 5 types: 'High Performance-High Centrality' (HP-HC), 'Network Leader-Low Technology Manufacturer' (NL-LTM), 'Network Leader-Distributor' (NL-D), 'High Performance-Network Outsider' (HP-NO), 'Low Performance-Isolated' (LP-I). Finally, sectoral and spatial policy implications are explored with the results of analysis.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.34-34
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• 2017

Various extracts of roots, stems, and leaves of Phalaenopsis Sogo Yukidian 'V3' were evaluated for total phenolics, total flavonoids, and antioxidant capacity. The conjugate form of stem samples contained the highest total phenolics ($5.092{\pm}0.739mg$ gallic acid equivalent per g dry weight） and the highest total flavonoids ($2.218{\pm}0.021mg$ rutin equivalent per g dry weight) was found in the hexane extract of leaves. The ethyl acetate extract of roots showed the maximum antioxidant activity as compared to other extracts. Of which, the $IC_{50}$ value of this sample were 0.070 mg/mL and 0.450 mg/mL in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and reducing power, respectively, while the lipid peroxidation inhibition (LPI) value was as 94.2% by ${\beta}$-carotene bleaching method. Five phenolic compounds including caffeic acid, syringic acid, vanillin, ellagic acid, and cinnamic acid were quantified by high-performance liquid chromatography (HPLC). It is suggested that roots of the hybrid Phalaenopsis Sogo Yukidian 'V3' can be explodited as an effective source of antioxidants.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1422-1430
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• 2016

Researches for oceans are limited to military purpose such as underwater sound detection and tracking system. Underwater acoustic communications with low-probability-of-interception (LPI) covert characteristics were received much attention recently. Covert communications are conducted at a low received signal-to-noise ratio to prevent interception or detection by an eavesdropper. This paper proposed optimal covert communication model based on direct sequence spread spectrum for underwater environments. Spread spectrum signals may be used for data transmission on underwater acoustic channels to achieve reliable transmission by suppressing the detrimental effect of interference and self-interference due to jamming and multipath propagation. The characteristics of the underwater acoustic channel present special problems in the design of covert communication systems. To improve performance and probability of interception, we applied BCJR(Bahl, Cocke, Jelinek, Raviv) decoding method and the direct sequence spread spectrum technology in low SNR. Also, we compared the performance between conventional model and proposed model based on turbo equalization by simulation and lake experiment.

• Atmosphere
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• v.28 no.2
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• pp.187-200
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• 2018

The heavy snowfall phenomenon with thunder and lightning occurred in Yeongdong coastal region on 20 January 2017. Amount of snow on that day was a maximum of 47 cm and was concentrated in a short time (2 hours) at the Yeongdong coastal area. The mechanism of thundersnow was investigated to describe in detail using observational data and numerical simulation (Weather Research and Forecast, WRF) applied lightning option. The results show that a convective cloud occurred at the Yeongdong coastal area. The east wind flow was generated and the pressure gradient force was maximized by the rapidly developed cyclone. The cold and dry air in the upper atmosphere has descended (so called tropopause folding) atmospheric lower layer at precipitation peak time (1200 LST). In addition, latent heat in the lower atmosphere layer and warm sea surface temperature caused thermal instability. The convective cloud caused by the strong thermal instability was developed up to 6 km at that time. And the backdoor cold front was determined by the change characteristics of meteorological elements and shear line in the east sea. Instability indexes such as Total totals Index (TT) and Lightning Potential Index (LPI) are also confirmed as one of good predictability indicates for the explosive precipitation of convective rainfall.