• Journal of Navigation and Port Research
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• v.38 no.3
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• pp.239-246
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• 2014

A study on the elution characteristics of biostimulating agents (sulfate and nitrate) from biostimulants which are used for in-situ bioremediation for the coastal sediment contaminated with organic matter was performed. The biostimulating agents were mixed with the coastal sediment, and then massed the mixture into ball. Two kinds of ball type biostimulant were prepared by coating the ball surface with two different polymers, cellulose acetate and polysulfone. A granular type biostimulant (GTB) was also prepared by impregnating a granular activated carbon in the biostimulating agent solution. The image of scanning electron microscopy for the biostimulant coated with cellulose acetate (CAB) showed that the inner side of the coating layer consisted of irregular and bigger size of pores, and the surface layer had tight structure like beehive. For the biostimulant coated with polyfulfone (PSB), the whole coating layer had a fine structure without pore. The elution rate of the biostimulating agents for the CAB was higher than that for the PSB, and the elution rate for the GTB was considerably higher than that for the PSB in distilled water as well as in sea water. The elution rate of the biostimulating agents in turbulent water flow was about 3 times higher than that in standing water, and the elution rate of nitrate was higher than that of sulfate from the stimulating agents.

• Journal of Korea Port Economic Association
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• v.26 no.4
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• pp.329-353
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• 2010

This paper deal with government logistics policy in related low carbon in China. The government policy of promoting low-carbon way is more dependent on the top-down enforcement rather than voluntary market principles. It will succeeded in transforming the environment-friendly image, to focus on creating a mindset the company can go on voluntary carbon-reduction. The three factors of low-carbon economy and the new energy and industrial development policy is technology and funding, and that most of the government's policy has a crucial role. Due to the nature of the Chinese economy, government policies impact on the development of the industry is very important, and even for China's industrial restructuring of the logistics industry in the areas of government policy support for green economic growth, its role is expected to be very large. In Future, Chinese government will promote low carbon policies through the optimization of the logistics network to reduce energy waste, pursue the low carbon-reduction of logistics machinery and equipment, and develop an mode to appropriate demand for green low-carbon economic growth.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.1 s.116
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• pp.37-43
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• 2007

In this.paper, we introduce design and implementation results of the single balanced diode mixer for European point-to-point microwave radio in order to improve flatness performance. When a resonator such as RF filter is integrated with a mixer, impedance characteristic of 50 ohm is maintained only in RF band, not in LO band resulting deterioration of flatness performance because of LO power variation on the diode. In the paper, we suggest a design method of mixer integrated with image rejection filter and LO harmonic filter to have a better performance of flatness using embedding electrical length between filter and mixer's port. Frequency specification of fabricated mixer is $21.2{\sim}22.6\;GHz$ for RF, $19.32{\sim}20.72\;GHz$ for LO and 1.88 GHz+/-50 MHz for IF, respectively. Measured results show conversion loss of 8.5 dB, flatness of 2 dB, input PldB of 8 dBm, IIP3 of 15 dBm under LO power level of 10 dBm. Return losses of RF, LO and IF port are under -12 dB, -10 dB and -5 dB, respectively. Isolations of LO/RF and LO/IF are 20 dB and 50 dB, respectively.

• Journal of Navigation and Port Research
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• v.40 no.3
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• pp.159-164
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• 2016

The goal of this study is to implement a communication system that can monitor the status of the nacelle using the power cable itself, without the dedicated communication lines such as an UTP cable and optical fiber for the offshore wind turbine. An inductive coupling powerline communication system for a MW class offshore wind turbine was proposed and its communication performance was demonstrated. The inductive couplers was designed for operation at up to 500 A using a ferrite composite materials. Field test was carried out on the wind farms of Jeju island. Using the iperf communication test program, we have obtained more than 15 Mbps data transmission rate through the 100 m power cable that was installed between the nacelle and the bottom of the power converter. In the data transmission stability test for a week, there was no failure ever. The minimum transmission rate was 15 Mbps and the average data rate was about 20 Mbps. Next, we have installed an infrared camera inside the nacelle in order to measure the temperature distribution and variation of the nacelle. The real-time thermal image taken by the camera was successfully sent to the monitoring system without error.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.406-414
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• 2018

The objective of this study was to analyze the effect of characteristics of maritime telemedicine (service quality, recognition or not of service, health counselling service experience or not) on seafarer's satisfaction, and also analyze the effect of seafarer's satisfaction on loyalty. This study's data was collected from the Research Report of Survey of telemedicine service subjects in 2017 conducted in the maritime telemedicine pilot project. However, only 103 seafarers who received maritime telemedicine (Tele-Monitering) services were analyzed statistically. The main results of this study were as follows. ⅰ) Better service quality led to higher levels of satisfaction, ii) High levels of seafarer's satisfaction led to high levels of loyalty, iii) Seafarers whose age is under 50 than 30 years old are less satisfied, ⅳ) In total boarding career, Seafarers with more than 5 years but less than 10 years were more satisfied than seafarers with less than 5 years, ⅴ) Seafarers with more than 10 years but less than 15 years were more satisfied than seafarers with less than 5 years, ⅵ) Seafarers with more than 15 years but less than 20 years were more satisfied than seafarers with less than 5 years, ⅶ) Also, Seafarers in excess of 20 years were more satisfied than seafarers with less than 5 years, In conclusion, ⅰ) Better service quality led to higher levels of satisfaction and loyalty. Accordingly, the improvement of service quality is not only an important factor in improving satisfaction and loyalty, but also plays an important role in forming a positive image of maritime telemedicine. ⅱ) Seafarers with younger age and lower overall total boarding career were more satisfied. It is believed that the seafarer who are willing to use telemedicine and who are willing to refer to others are young.

• Journal of Minimally Invasive Surgery
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• v.21 no.4
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• pp.168-176
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• 2018

Purpose: Robotic-associated minimally invasive surgery is a novel method for overcoming some limitations of laparoscopic surgery. This study aimed to evaluate the outcomes (postoperative pain, cosmesis, surgeon's workload) of single-incision robotic cholecystectomy (SIRC) vs. single-incision laparoscopic cholecystectomy (SILC) vs. conventional three-port laparoscopic cholecystectomy (3PLC). Methods: 134 patients who underwent laparoscopic or robotic cholecystectomy at a single center during 2016~2017 were enrolled. Prospectively collected data included demographics, operative outcomes, questionnaire regarding pain and cosmesis, and NASA-Task Load Index (NASA-TLX) scores for surgeon's workload. Results: 55 patients underwent SIRC, 29 SILC, and 50 3PLC during the same period. 3PLC patient group was older than the others (SIRC vs. SILC vs. 3PLC: 48.1 vs. 42.2 vs. 54.1 years, p<0.001). Operative time was shortest with 3PLC (44.1 vs. 38.8 vs. 25.4 min, p<0.001). Estimated blood loss, postoperative complications, and postoperative stay were similar among the groups. Pain control was lowest in the 3PLC group (98.2% vs. 100% vs. 84.0%, p=0.004), however, at 2 weeks postoperatively there were no differences among the groups (p=0.374). Cosmesis scores were also worst after 3PLC (17.5 vs. 18.4 vs. 13.3, p<0.001). NASA-TLX score was highest in the SILC group (21.9 vs. 44.3 vs. 25.2, p<0.001). Conclusion: Although SIRC and SILC take longer than 3PLC, they produce superior cosmetic outcomes. Compared with SILC, SIRC is more ergonomic, lowering the surgeon's workload. Despite of higher cost, SIRC could be an alternative for treating gallbladder disease in selected patients.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.659-668
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• 2021

The purpose of this study is to propose a ventilation corridor management plan to improve the thermal environment for Busan Metropolitan City. To this end, the characteristics of hot and cool spots in Busan were identified by conducting spatial statistical analysis, and thermal image data from Landsat-7 satellites and major ventilation corridors were analyzed through WRF meteorological simulation. The results showed the areas requiring thermal environment improvement among hot spot areas were Busanjin-gu, Dongnae-gu, industrial areas in Yeonje-gu and Sasang-gu, and Busan Port piers in large-scale facilities. The main ventilation corridor was identified as Geumjeongsan Mountain-Baekyangsan Mountain-Gudeoksan Mountain Valley. Based on the results, the ventilation corridor management strategy is suggested as follows. Industrial facilities and the Busan Port area are factors that increase the air temperature and worsen the thermal environment of the surrounding area. Therefore, urban and architectural plans are required to reduce the facility's temperature and consider the ventilation corridor. Areas requiring ventilation corridor management were Mandeok-dong and Sajik-dong, and they should be managed to prevent further damage to the forests. Since large-scale, high-rise apartment complexes in areas adjacent to forests interfere with the flow of cold and fresh air generated by forests, the construction of high-rise apartment complexes near Geumjeongsan Mountain with the new redevelopment of Type 3 general residential area should be avoided. It is expected that the results of this study can be used as basic data for urban planning and environmental planning in response to climate change in Busan Metropolitan City.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.2
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• pp.7-13
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• 2002

When a USB digital camera is used for PC video-conference applications, motion picture data need to be transferred to the PC through the USB port. Due to the mismatch between the data rates of the USB and the motion picture, data compression should be performed before the transmission from the USB. While many motion picture compression algorithms require large intermediate memory space, the JPEG algorithm does not need to store an entire frame for the compression. Instead, a relatively small buffer is required at the input of the JPEG compression engine to resolve the inconsistency between the orders of the inputted data and the consumed data. Data reordering can be easily implemented using a double buffering scheme, which still requires a considerable size of memory. In this paper, a novel memory management scheme is proposed to avoid the double buffering. The proposed memory architecture requires a small amount of memory and a simple address generation scheme, resulting in overall cost reduction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.12
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• pp.691-698
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• 2014

An L-band single side band(SSB) mixer with CMOS switches and a C-band quadrature voltage-controlled oscillator(QVCO) have been developed using the TowerJazz 0.18-um RFCMOS process. The SSB mixer exhibits a conversion gain of 6.6 ~ 7.5 dB with a 70-dBc image rejection ratio and 65-dBc port isolation. The oscillation frequency range of the QVCO is 6.2 ~ 6.7 GHz with an output power of 4~6 dBm. For measurement, 1.8 V supply voltage is used while drawing 36 mA for the mixer and 23 mA for the QVCO.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.9
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• pp.807-813
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• 2015

In the present study, an interferometer system, which integrates the laser sensitivity control technique based on the theory of electronic speckle pattern interferometry, one of non-contact non-destructive analysis methods, was developed. This interferometry system receives an image from CCD cameras for each reference and object, and compares the photosensitivity of the object and reference images from imagification. For the purpose of this study, the photosensitivity of object and reference light is measured with power meters, and the amount of light was controlled with an ND filter with a reference light port matching photosensitivity. Using the plate specimen as the object, 0.6, 0.9, 1.2, and $1.5{\mu}m$ of out-plane deformation was made, and images were compared according to the difference in photosensitivity. After analysis, larger object deformations showed larger numbers of stripe patterns. Images became clearer and data error was reduced when the photosensitivity of object and reference light matched.