• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.17-26
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• 2016

This work proposes a 12b 60MS/s 0.18um CMOS Flash-SAR ADC for various systems such as wireless communications and portable video processing systems. The proposed Flash-SAR ADC alleviates the weakness of a conventional SAR ADC that the operation speed proportionally increases with a resolution by deciding upper 4bits first with a high-speed flash ADC before deciding lower 9bits with a low-power SAR ADC. The proposed ADC removes a sampling-time mismatch by using the C-R DAC in the SAR ADC as the combined sampling network instead of a T/H circuit which restricts a high speed operation. An interpolation technique implemented in the flash ADC halves the required number of pre-amplifiers, while a switched-bias power reduction scheme minimizes the power consumption of the flash ADC during the SAR operation. The TSPC based D-flip flop in the SAR logic for high-speed operation reduces the propagation delay by 55% and the required number of transistors by half compared to the conventional static D-flip flop. The prototype ADC in a 0.18um CMOS demonstrates a measured DNL and INL within 1.33LSB and 1.90LSB, with a maximum SNDR and SFDR of 58.27dB and 69.29dB at 60MS/s, respectively. The ADC occupies an active die area of $0.54mm^2$ and consumes 5.4mW at a 1.8V supply.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.242-247
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• 1999

The characteristics of waste heat effluents from 11 industrial complexes of 7 areas were analyzed to investigate the possibility of waste heat recovery of huge amount of waste heat producing from various industrial complexes. This study presents a part of the research work for the industrial waste heat for development of energy integrated network system in broad city area, which will utilize industrial waste heat for residential and commercial areas, where they are located at some distances from the complexes. The amount of waste heat from the investigated complexes was detected as 148,913 TOE/year. However, It was analyzed 83% of the waste heat was analyzed the temperature range from 0$^{\circ}C$ to 200$^{\circ}C$. Also, it was evaluated that 82% of waste heat was exhausted by flue gases. Especially, the characteristics of waste heat for the areas where most heat concentrated, such as Tae-gu industrial complex, Ul-san petrochemitry complex, Yio-chun petrochemistry complex, and Chun-ju industrial complex were investigated more precisely. Total amount of waste heat discharged from these four areas were analyzed 114,402 TOE/year, which was occupied as 77% of the total waste heat for the studied areas, and 87% of the waste heat from the industries was exhausted by flue gaseous phase and temperature range was from 0$^{\circ}C$ to 200$^{\circ}C$ 18.1 million TOE/year waste heat was released from the fossil fuel power plants, however 95% of waste heat was analyzed as cooling water from surface condensers at power plants. The temperature range was measured from 27$^{\circ}C$ to 34$^{\circ}C$, which are unable to utilize due to its low temperature. Otherwise, 5% (894,800 TOE/year) waste heat released from power plants were observed as flue gas, which temperature ranged from 90$^{\circ}C$ to 170$^{\circ}C$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.678-681
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• 2003

In this paper, we aims to develop a microcontroll er-based portable pulse oximeter using Compact Flash Interface. First, portable pulse oxineter system is designed to record 2 channel of biosignals simultaneously, including 1 channel of SpO$_2$ and 1 channel of pulse rate. It is very small and portable. Besides, the system makes it possible to measure a patients condition without an additional medical equipment. We tried to solve the problems generated by a patient's motion. That is, we added an analog circuit to a traditional pulse oximeter in order to eliminate the change of the base line. And we used 2D sector algorithm. As present, SpO$_2$ modules are completed. But there are still many further development needed in order to enhance the function. Especially, compact flash interface remains the most to complete. Second, ECG monitoring system uses almost same as present 3-lead ECG system. But we focus on the analog part, especially in filter. The proposed filter is composed of two parts. One is a filter to remove the power-line interface. The other is a filter to remove the baseline drift. A filter to remove the power-line and the baseline drift is necessarily used in the ECG system. The implemented filter have three features; minimizing the distortion in DC component, removing the harmonic component of power-line frequency. Using compact flash interface, we can easily transfer a patient's personal information and the measured signal data to a network based server environment. That means, it is possible to implement a patient's monitoring system with low cost.

• Journal of Convergence Society for SMB
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• v.3 no.2
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• pp.27-32
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• 2013

Wireless Body Area Networks (WBAN) have been made possible by the emergence of small and lightweight wireless systems such as Bluetooth, enabled devices and PDAs. Antennas are an essential part of any WBAN system and due to various technical requirements and physical constraints, careful consideration of their design and deployment is needed. This paper is proposing on the design of wearable antenna as parts of clothing to serve communications functions, such as tracking and navigation in health care applications. The substrates of the wearable antennas will be made from textile materials and since it is wearable, it should have a small size, be light weight, low maintenance, and unobtrusive. This proposed paper will also investigate the influence of different parameters for wearable antenna including types of textile/substrate to ensure that the antenna design satisfies WBAN requirements. The characteristics and behavior of the antenna need to adhere to specifications set by wireless standards and system technology requirements. This means that the transmitting and receiving frequency bands of the various units need to be chosen accordingly. Since there are restrictions on the level of power to which the human body can be exposed to, the antenna as well as other RF system components must be designed to meet these restrictions. Antenna gain, which directly affects power transmitted, is a critical parameter in ensuring power levels fall within the safety guidelines and so will be of primary importance in the design. The electromagnetic interaction between WBAN antennas and devices and the human body will also be explored.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.172-187
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• 2019

Knowledge of intangible cultural heritage is usually disseminated through word-of-mouth and actions rather than written records. Thus, people assemble to teach others about it and form communities. Accordingly, to understand and spread information about intangible cultural heritage properly, it is necessary to understand not only their attributes but also a community's relational characteristics. Community members include specialized transmitters who work under the auspices of institutions, and general transmitters who enjoy intangible cultural heritage in their daily lives. They converse about intangible cultural heritage in close relationships. However, to date, research has focused only on professionals. Thus, this study focused on the roles of general transmitters of intangible cultural heritage information by investigating intangible cultural heritage communities centering around Jeongseon Arirang; a social network analysis was performed. Regarding the research objectives presented in the introduction, the main findings of the study are summarized as follows. First, there were 197 links between 74 members of the Jeongseon Arirang Transmission Community. One individual had connections with 2.7 persons on average, and all were connected through two steps in the community. However, the density and the clustering coefficient were low, 0.036 and 0.32, respectively; therefore, the cohesiveness of this community was low, and the relationships between the members were not strong. Second, 'Young-ran Yu', 'Nam-gi Kim' and 'Gil-ja Kim' were found to be the prominent figures of the Jeongseon Arirang Transmission Community, and the central structure of the network was concentrated around these three individuals. Being located in the central structure of the network indicates that a person is popular and ranked high. Also, it means that a person has an advantage in terms of the speed and quantity of the acquisition of information and resources, and is in a relatively superior position in terms of bargaining power. Third, to understand the replaceability of the roles of Young-ran Yu, Nam-gi Kim, and Gil-ja Kim, who were found to be the major figures through an analysis of the central structure, structural equivalence was profiled. The results of the analysis showed that the positions and roles of Young-ran Yu, Nam-gi Kim, and Gil-ja Kim were unrivaled and irreplaceable in the Jeongseon Arirang Transmission Community. However, considering that these three members were in their 60s and 70s, it seemed that it would be necessary to prepare measures for the smooth maintenance and operation of the community. Fourth, to examine the subgroup hidden in the network of the Jeongseon Arirang Transmission Community, an analysis of communities was conducted. A community refers to a subgroup clearly differentiated based on modularity. The results of the analysis identified the existence of four communities. Furthermore, the results of an analysis of the central structure showed that the communities were formed and centered around Young-ran Yu, Hyung-jo Kim, Nam-gi Kim, and Gil-ja Kim. Most of the transmission TAs recommended by those members, students who completed a course, transmission scholarship holders, and the general members taught in the transmission classes of the Jeongseon Arirang Preservation Society were included as members of the communities. Through these findings, it was discovered that it is possible to maintain the transmission genealogy, making an exchange with the general members by employing the present method for the transmission of Jeongseon Arirang, the joint transmission method. It is worth paying attention to the joint transmission method as it overcomes the demerits of the existing closed one-on-one apprentice method and provides members with an opportunity to learn their masters' various singing styles. This study is significant for the following reasons: First, by collecting and examining data using a social network analysis method, this study analyzed phenomena that had been difficult to investigate using existing statistical analyses. Second, by adopting a different approach to the previous method in which the genealogy was understood, looking at oral data, this study analyzed the structures of the transmitters' relationships with objective and quantitative data. Third, this study visualized and presented the abstract structures of the relationships among the transmitters of intangible cultural heritage information on a 2D spring map. The results of this study can be utilized as a baseline for the development of community-centered policies for the protection of intangible cultural heritage specified in the UNESCO Convention for the Safeguarding of Intangible Cultural Heritage. To achieve this, it would be necessary to supplement this study through case studies and follow-up studies on more aspects in the future.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.516-522
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• 2014

This study was conducted to investigate the impact of the anthropogenic factors affecting distribution of the Red-crowned Crane and White-naped Crane wintering in Cheorwon, Korea. Especially, it was investigated that the impact power and its range of the anthropogenic effect to the feeding flock density in cranes due to the paved road, residential area, military facilities and greenhouse density. The Red-crowned Crane and the White-naped Crane showed the similar preference and sensitivity against anthropogenic factors, because correlation of feeding flock density of the Red-crowned Crane and White-naped Crane was similar in the same site. The feeding flock density of the cranes near the residential area was lower than that of area far from the area, and tended to increase within 2.5 km distance. The increasing tendencies of feeding flock density from military facilities and high traffic volume road were similar, but the density in military facilities increased within 0.8 km, and the density from high traffic volume road increased within 2 km. This results suggested that military facilities and the road with high traffic volume made significant influence on foraging densities to the certain range. As the distance from the road with low traffic volume increased, feeding flock density tended to decrease. The area near the low traffic volume road had high feeding flock density because remaining rice grains were preserved by intermittent disturbances in that area. If the density of greenhouse is lower than $40/km^2$, feeding flock density in the low greenhouses density area was higher than high greenhouses density area. However, there was no difference in the feeding flock density if the density of the green houses is higher than $40/km^2$.

• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.298-306
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• 2016

With the advent of Internet of Things (IoT) technology that allows the communications between things and devices over the Internet, a lot of researches on the IoT services, such as smart home or healthcare, have been progressed. In the existing machine-to-machine (M2M) communications, however, since the underlying link-layer technologies, such as Bluetooth or ZigBee, do not use the Internet Protocol (IP) communication, those technologies are not suitable to provide the IoT services. Accordingly, this paper discusses how to provide the Internet services in the M2M communication, and propose an implementation of the Constrained Application Protocol (CoAP) over 6LoWPAN for providing IoT services in the BLE networks. Based on the implementation, we compared the performance between HTTP and CoAP for IoT communications. From the experimental results, we can see that the CoAP protocol gives better performance than the HTTP protocol with two times higher throughput, 21% faster transmission time, and 22% smaller amount of generated packets.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.352-360
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• 2008

Recently Task Group (TG) 4 of the Institute of Electrical and Electronics Engineers (IEEE) 802.15a has been recommended a system with ranging capability in existence of multiple Simultaneous operating piconets (SOPs) as well as low-cost, low-power. According to the ranging service, coherent and non-coherent based ranging schemes using ternary code have been adopted as a standard. However it is hard to estimate an accurate time of arrival (TOA) in case of using direct sequence based TOA estimation method because pulse repetition interval (PRI) offered by TG is more limited than the maximum excess delay (MED) of channel. To mitigate inter pulse interference (IPI) problem, this paper proposes a non-coherent TOA estimation scheme using non-periodic transmission (NPT) pattern. The proposed receiver is based on a non-coherent energy detection considering with motivation of low rate wireless personal area network (LR-WPAN). TOA information is estimated via proper comparison with a prescribed threshold after the sliding correlation and search back window (SBW) process for reducing TOA error. To verify the performance of proposed ranging scheme, two distinct channel models approved by IEEE 802.15.4a TG are considered. According to the simulation results, we could conclude that the proposed scheme have performed better performance than the conventional method on the existence of multiple SOPs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1027-1034
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• 2005

IEEE802.15.4a, which is started to realize the PHY layer including high precision ranging/positioning and low data rate communication functions, requires a simple and low power consumable transceiver architecture. To satisfy this requirements, the simple noncoherent on-off keying (OOK) UWB transceiver with the parallel energy window banks (PEWB) giving high precision signal processing interface is proposed. The flexibility of the proposed system in multipath fading channel environments is acquired with the pulse and bit repetition method. To analyze the bit error rate (BER) performance of this proposed system, a noise model in receiver is derived with commonly used random variable distribution, chi-square. BER of $10^{-5}$ under the line-of-sight (LOS) residential channel is achieved with the integration time of 32 ns and signal to noise ratio (SNR) of 15.3 dB. For the non-line-of-sight (NLOS) outdoor channel, the integration time of 72 ns and SNR of 16.2 dB are needed. The integrated energy to total received energy (IRR) for the best BER performance is about $86\%$.

• Journal of Korea Port Economic Association
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• v.40 no.3
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• pp.115-130
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• 2024

This study was conducted to identify the relative importance of the decision factors that should be given priority in order for Gwangyang Port Container Terminal to transform into an eco-friendly port based on carbon neutrality. To this end, three upper decision factors and 12 lower decision factors were derived, and a survey was conducted targeting shipping port experts and port users. The priorities were identified using the Fuzzy-Analytic Hierarchy Process(Fuzzy-AHP) technique. As a result, the importance of the three upper priority factors was evaluated in the order of low-carbon infrastructure construction, legal system improvement, and operational management efficiency. As a result of the composite weight analysis calculated by multiplying the importance of the upper factor by the lower factor, the comprehensive combined importance of the 12 lower-level factors was highest in ① conversion to eco-friendly power such as existing unloading equipment, followed by ② expansion of renewable energy in ports, ③ introduction of energy-saving equipment and facilities, ④ establishment of a circular hydrogen sharing network in the Gwangyang Bay area, ⑤ establishment and implementation of a low-carbon port mid- to long-term strategy, ⑥ provision of incentives to users to achieve carbon neutrality, ⑦ implementation of regulatory measures such as a carbon burden system, ⑧ establishment of an eco-friendly port management system, ⑨ introduction of a mandatory AMP use system, ⑩ expansion of the low-speed operation program, ⑪ expansion of operation of a carbon-neutral working-level organization and education, and ⑫ greenhouse gas monitoring in ports and nearby areas. This study provided the basic basis and foundation through an analysis of the priority of decision factors for Gwangyang Port Container Terminal to leap forward as a global carbon-neutral port, and presented objective criteria for introduction decision factors that should be referenced by the government, local governments, port authorities, and shipping and port-related organizations.