Reducing hops without extra power: Impact of deployment height on low-power multihop wireless network

Jeong, Hoon,Lee, Changwon,Ryu, Jaehong,Choi, Byung-Chul,Ko, JeongGil,Paek, Jeongyeup Taylor & Francis 2017 INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWOR Vol.13 No.9

Using Pulse-Front Tilt to Measure Laser Pulses Less Than 100 Picoseconds in Duration

Jeong, Hoon Optical Society of Korea 2015 한국광학회지 Vol.26 No.6

We demonstrate a frequency-resolved optical grating (FROG) device for measuring the intensity and phase versus time of several-tens-of-picoseconds laser pulses, using a thick nonlinear optical crystal. The huge pulse-front tilt generated by a holographic grating increases the temporal range of the device, which can make a single-shot measurement of laser pulses less than 100 ps in duration. To verify the measurement technique, we generate double pulses using a Michelson interferometer. The measured duration of a single pulse is about 300 fs and the measured maximum delay of two pulses is 60 ps, which implies that the proposed FROG device can measure laser pulses with maximum pulse width of about 120 ps.

Output power improvement in an Yb-doped fiber laser with an additional unpumped Yb-doped fiber

Jeong, Hoon,Park, Hyoyeong,Kim, Seungtaek,Kim, Jongseok,Byun, Chulsoo,Kim, Cheolho Springer-Verlag 2012 Optical review Vol.19 No.2

The Design and Implementation of a DVB-RCS Modulator Using Single FPGA

Jeong, Hoon,Lee, Seung-Joon,Cho, Yong-Hoon 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-

This paper presents the design and implementation of a DVB-RCS return channel modulator using FPGA. The DVB-RGS standard was finalized by DVB in 2000. It provides an efficient way for accessing Internet via satellite. In the DVB-RCS standard, the Multi-Frequency Time Division Multiple Access (MF-TDMA) is used for return channel.. To support the DVB-RCS standard, the return channel modulator has to operate differently timeslot by timeslot, since different timeslots may have different frequencies, transmit symbol rates, or channel codes. For implementation of a DVB-RCS modulator, just one XILINX VIRTEX-E 1600 FPGA is used with some peripherals. This FPGA is designed to have three functional modules, the Parameter store and management module, the Burst generation module, and the Modulation module. The results of this paper show the possibility of the one-chip solution for the DVB-RCS modulator.

이주(移住)의 서사(敍事)와 고려인 공동체의 미래 ― 광주 고려인마을 거주 고려인의 구술생애담을 대상으로 ―

한정훈 ( Han¸ Jeong-hoon ) 전남대학교 호남학연구원 2020 호남학 Vol.0 No.68

본 논문은 광주 고려인마을에 거주하는 이주민 고려인의 구술생애담을 대상으로 개인과 공동체의 문제를 다양한 층위에서 살펴보는 것을 목적으로 한다. 고려인은 강제 이주 후에 소비에트 체제에 철저히 동화하기 시작했다. 그리고 고려인은 ‘소비에트 인민’으로서 집단의 정체성을 구성하면서 구소련 사회에 나름의 입지를 구축했다. 구소련이 해체된 이후 중앙아시아 국가들은 정치·경제·사회적 측면에서 불안정이 계속되었고, 고려인은 기존의 정체성과 사회적 지위를 유지할 수 없었다. 경제 발전을 이룩한 한국은 고려인이 이주하기에 매력적인 장소였다. 하지만 한국은 낭만적으로 상상했던 ‘조상의 나라’가 아니었다. 신자유주의 체제와 각종 효율성이 일상을 지배하는 장소였다. 고려인은 외모가 비슷할 뿐, 현대의 한국인과 동일할 수 없는 위치에 있음을 깨닫는다. 끊임없이 접촉해 오는 타자적 시선은 한국 사회에서 나름의 사회적 정체성 정립을 고려인에게 요구했다. 고려인의 한국 이주가 시간이 지나면서 세대를 달리하며 이어지고 있다. 본 연구는 고려인의 한국 이주가 시간의 흐름 속에서 어떤 모습으로 진행되었고, 그 과정에서 고려인 개인과 그들의 공동체가 어떤 대응을 하였는가를 살펴보고자 한다. 나아가 고려인의 이주 세대가 바뀌어감에 따라 어떤 문제들이 새롭게 적층해 가고 있는 살펴보고자 한다. The purpose of this study is to examine the problems of individuals and communities from various levels focusing on oral life narratives of migrants, Goryeo people living in the Goryeo people village in Gwangju city. Goryeo people began to assimilate thoroughly into the Soviet system after the forced migration. And Goryeo people, as 'Soviet People', formed their own position in the former Soviet Union, establishing an identity of the group. After the dissolution of the former Soviet Union, Central Asian countries continued to be unstable in terms of politics, economy and society, and Goryeo people were unable to maintain their existing identity and social status. Korea, which achieved economic development, was an attractive place for Goryeo people to migrate. But Korea wasn't the ‘country of ancestors’ that was romantically imagined. The country is where the neoliberal system and various efficiencies were the dominance of everyday life. Goryeo people realize that their appearances are similar, and that they cannot be identical to modern Koreans. The constant contact with people with third-party eyes demanded Goryeo people to establish their own social identity in Korean society. Goryeo people's migration to Korea continues over generations as time goes. This study attempts to examine how Goryeo people's migration to Korea has progressed, and in the process, how Goryeo people and their communities responded. Furthermore, this study attempts to investigate what problems are newly stacked up as the migration generation of Goryeo people changes.

A Study on the Utilization of the National Occupational Competency Standards for the Development of Security Field

Jeonghoon Ha(Jeonghoon Ha) J-INSTITUTE 2022 International Journal of Terrorism & National Secu Vol.7 No.2

Purpose: In Korea's industrial sites, the state standardizes the skills required to perform duties and supports to foster the field-oriented talents, yet the use of the National Occupational Competency Standards in the security industry is very inadequate. Method: In this study, the current status of the security industry and the operation of the National Occupa-tional Competency Standards are reviewed, and the National Occupational Competency Standards for the devel-opment of the security industry are conducted based on the interviews with the experts applying to the security industry using the National Occupational Competency Standards towards the efficient use of the Standards. Results: In the security industry, the National Occupational Competency Standards are not functioning properly given the dual contents provided by the existing Security Services Industry Act and the new National Occupational Competency Standards. Accordingly, it is required to change the legislative system which can more actively utilize the Security Services Industry Act and National Occupational Competency Standards and further improve the National Occupational Competency Standards. Conclusion: For the development of the security industry, this study presents the following conclusions. First, in the security industry and the NCS-based education system, the curriculum of the Security Services Industry Act and the education system of the NCS must be unified to reestablish the curriculum. Second, the classification of the duties of the Security Services Industry Act and the level of the NCS according to the occupational rating must be reestablished in a systematic and progressive direction by comprehensively examining the industrial reality and foreign cases. Third, it must be redeveloped as a comprehensive and efficient model by collecting the opin-ions of experts in each field for the inspection of the security industry and the NCS-based system.

The effects of a newsletter on bedding control on house dust mite allergen concentrations in childcare centers in Korea

Jeonghoon Kim,Kyoung Yong Jeong,Ho-Jang Kwon,Heasuk Yang,Hye Yung Yum,Seon Ah Lee,Chae-Bong Kim,Hyunjung Kim,Wan Ryung Lim,Soyoung Hong,Kyoosang Kim 환경독성보건학회 2015 환경독성보건학회지 Vol.30 No.-

Objectives: Bedding in childcare centers (CCCs) can hold house dust mite (HDM) allergens. This study examined whether HDM allergen levels can be reduced through the distribution of an educational newsletter on bedding control to parents of CCC children in Korea. Methods: All 38 CCCs were measured for Der 1 (sum of Der f 1 and Der p 1) concentrations on classroom floors and bedding before the intervention. Educational newsletters on children’s bedding control were sent to 21 CCCs by mail, and teachers were asked to distribute the newsletters to the parents of the children (intervention group). The remaining 17 CCCs were not sent newsletters (control group). The measurement of Der 1 concentrations in 38 CCCs was repeated after the intervention. Dust samples were collected with a vacuum cleaner and analyzed using enzyme-linked immunosorbent assay methods. Results: The Der 1 concentrations on the bedding were significantly higher than those on the floors in 38 CCCs at baseline (p <0.05). Although changes of the Der 1 concentrations for the control group (n=17) were not significant, Der 1 concentrations for the intervention group (n=21) decreased significantly from 2077.9 ng/g dust to 963.5 ng/g dust on the floors and from 3683.9 ng/g dust to 610.4 ng/g dust on bedding (p <0.05). Conclusions: The distribution of educational newsletters on bedding control to parents may be an effective means of controlling HDMs in CCCs.

Association of serum free thyroxine and glucose homeostasis: Korea National Health and Nutrition Examination Survey

( Jeonghoon Ha ),( Jeongmin Lee ),( Dong-jun Lim ),( Jung-min Lee ),( Sang-ah Chang ),( Moo-il Kang ),( Min-hee Kim ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.0

Background/Aims: Thyroid hormones are involved in wide range of glucose metabolism functions. Overt thyroid dysfunctions are related to altered glucose homeostasis. However, it is not conclusive as to whether subtle changes in thyroid hormones within normal ranges can induce alterations in glucose homeostasis. The aim of this study was to evaluate the association between thyroid hormone and glucose homeostasis parameters in subjects without overt thyroid dysfunction based on nationwide population data. Methods: In the Sixth Korea National Health and Nutrition Examination Survey 2015 (n = 7,380), data were collected from subjects with insulin and thyroid function measurements who were older than 19-years-old. After the exclusion of 5,837 subjects, a total of 1,543 patients were included in the analysis. Subjects were categorized into the quartiles of the free thyroxine (FT4). Fasting glucose, insulin, homeostatic model assessment of insulin resistance and hemoglobin A1c (HbA1c) levels were considered to be glucose homeostasis parameters. Results: Subjects with the highest FT4 quartile showed significantly lower fasting insulin and HbA1c levels. A significant inverse correlation FT4 and HbA1c levels was observed (β = -0.261, p = 0.025). In the logistic regression analysis, the highest quartile of FT4 was demonstrated to lower the risk of HbA1c to a greater degree than the median by approximately 40%, after adjusting for confounders, compared to the lowest quartile (p = 0.028). Conclusions: We demonstrated subjects with a lower FT4 quartile exhibited high risk of HbA1c levels above the median value in a representative Korean population. Subjects with the lowest FT4 quartile should be cautiously managed in terms of altered glucose homeostasis.

Characteristic Analysis of Auditory Stimuli Utilizing the Sound Source of Ultrasonic Band and the Audible Frequency Band and Cerebral Activation State Changes

Jeonghoon Shin,Minji Kim,Sojeong Lee 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.10

Neurofeedback, which is considered an alternative medicine, is a training that changes the cerebral activation state by a patient's own efforts. New Neurofeedback users often have a hard time learning to control their own brain waves. For this reason, many users give up on Neurofeedback therapy prematurely. Neurofeedback advocates have been studying a variety of brain activation state control methods to develop easier Neurofeedback therapies to overcome this defect. Humans receive a variety of external information with the help of various sensory organs such as the eyes and ears. This information is recognized by the cerebrum, and as a result it induces changes in the activation state of the brain. Auditory stimulation of external stimuli is perceived as sound by stimulating the brain through air conduction. In general, the auditory stimulus bandwidth from 20Hz to 20KHz is used. Auditory stimulus of ultrasound higher than 22KHz is not used as an external stimulus to induce the brain activation state change, since humans cannot hear beyond this bandwidth. It is known that auditory stimulus of ultrasound bandwidth directly stimulates the cochlea of the inner ear and can induce changes in the brain activation state. However, no specific research results that compare the difference between the audible and the ultrasound stimulus has been presented, so there are limitations utilizing the ultrasound bandwidths in practical applications. For this reason, this study has analyzed changes in brain activation utilizing the auditory stimulation in audible and in ultrasound frequency. The research result of this study can be applied in a variety of applications, which uses ultrasound auditory stimulus.

Field Implementation of Voltage Management System (VMS) into Jeju Power System in Korea

Jeonghoon Shin,Suchul Nam,Jiyoung Song,Jaegul Lee,Sangwook Han,Baekkyung Ko,Yongho An,Taekyun Kim,Byungjun Lee,Seungmook Baek 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

This paper presents the results of field tests on Voltage Management System (VMS) using hybrid voltage control, which utilizes coordinated controls of various reactive power resources such as generators, FACTS and switched shunt devices to regulate the pilot bus voltage in a voltage control area. It also includes the results of performance test on RTDS-based test bed in order to validate the VMS before installing it in Jeju power system. The main purpose of the system is adequately to regulate the reactive power reserve of key generators in a normal condition with coordination of discrete shunt devices such as condensers and reactors so that the reserves can avoid voltage collapse in emergency state in Jeju system. Field tests in the automatic mode of VMS operation are included in steady-states and transient states. Finally, by the successful operation of VMS in Jeju power system, the VMS is proved to effectively control system voltage profiles in steady-state condition, increase system MVAR reserves and improve system reliability for pre- and post-contingency.