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Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Particle Size Analysis of Cadmium Aerosol for Cadmium Inhalation Toxicology Study (766ppm Cadmium Nebulizing Solution) (카드뮴의 흡입독성 연구를 위해 설계된 에어로졸 발생장치에서 발생된 카드뮴 에어로졸의 입경분석(766ppm 카드뮴 네뷸라이징 용액))

  • Jeung Jae Yeal;Milton Donald K.;Kim Tae Hyeung;Lee Jong Young;Jahng Doo Sub;Kang Sung He;Song Young Sun;Lee Ki Nam
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.16 no.5
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    • pp.1035-1041
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    • 2002
  • Ultrasonic nebulizer with the application of new engineering methodology and the design of electronic circuit and 766ppm Cd nebulizing solution were used to generate cadmium aerosol for inhalation toxicology study. The results of particle size analysis for cadmium aerosol were as following. The highest particle counting for source temperature 20℃ was 43.449 x 10³ in inlet temperature 250℃ and particle diameter 0.75㎛. The highest particle counting for source temperature 50℃ was 43.211 x 10³ in inlet temperature 100 ℃ and particle diameter 0.75㎛. The highest particle counting for source temperature 70℃ was 41.917x10³ in inlet temperature 250℃ and particle diameter 0.75㎛. The ranges of geometric mean diameter(GMD) were 0.677-1.009㎛ in source temperature 20℃, 0.716-0.963㎛ in source temperature 50℃, and 0.724-0.957㎛ in source temperature 70℃. The smallest GMD was 0.677㎛ in source temperature 20℃ and inlet temperature 20℃. and the largest GMD was 1.009㎛ in source temperature 20℃ and inlet temperature 20℃. The ranges of geometric standard deviation(GSD) were 1.635-2.101 in source temperature 20℃. 1.676-2.073 in source temperature 50℃, and 1.687-2.051 in source temperature 70℃. The lowest GSD was 1.635 in source temperature 20℃ and inlet temperature 20℃, and the highest GSD was 2.101 in source temperature 20℃ and inlet temperature 200℃. Aerosol generated for cadmium inhalation toxicology study was polydisperse aerosol. The ranges of mass median diameter(MMD) were 1.399-5.270㎛ in source temperature 20℃. 1.593-4.742㎛ in source temperature 50℃, and 1.644-4.504㎛ in source temperature 70℃. The smallest MMD was 1.399㎛ in source temperature 20℃ and inlet temperature 20℃, and the largest MMD was 5.270㎛ in source temperature 20℃ and inlet temperature 200℃. Increasing trends for GMD, GSD, and MMD were observed with same source temperature and increase of inlet temperature. MMD for inhalation toxicology testing in EPA guidance is less than 4㎛. In our results. inlet temperature 20 and 50℃ in source temperature 20℃, and inlet temperature 20 to 150℃ in source temperature 50 and 70℃ were conformed to the EPA guidance. MMD for inhalation toxicology testing in OECD and EU is less than 3㎛. In our results, inlet temperature 20 and 50℃ in source temperature 20, 50, and 70℃ were conformed to the OECD and EU guidance.

IPv6 Migration, OSPFv3 Routing based on IPv6, and IPv4/IPv6 Dual-Stack Networks and IPv6 Network: Modeling, and Simulation (IPv6 이관, IPv6 기반의 OSPFv3 라우팅, IPv4/IPv6 듀얼 스택 네트워크와 IPv6 네트워크: 모델링, 시뮬레이션)

  • Kim, Jeong-Su
    • The KIPS Transactions:PartC
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    • v.18C no.5
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    • pp.343-360
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    • 2011
  • The objective of this paper is to analyze and characterize to simulate routing observations on end-to-end routing circuits and a ping experiment of a virtual network after modeling, such as IPv6 migration, an OSPFv3 routing experiment based on an IPv6 environment, and a ping experiment for IPv4/IPv6 dual-stack networks and IPv6 network for OSPFv3 routing using IPv6 planning and operations in an OPNET Modeler. IPv6 deployment based largely on the integrated wired and wireless network was one of the research tasks at hand. The previous studies' researchers recommended that future research work be done on the explicit features of both OSPFv3 and EIGRP protocols in the IPv4/IPv6 environment, and more research should be done to explore how to improve the end-to-end IPv6 performance. Also, most related work was performed with an IPv4 environment but lacked studies related to the OSPFv3 virtual network based on an end-to-end IPv6 environment. Hence, this research continues work in previous studies in analyzing IPv6 migration, an OSPFv3 routing experiment based on IPv6, and a ping experiment for IPv4/IPv6 dual-stack networks and IPv6 network for OSPFv3 routing. In the not too distant future, before enabling the default IPv6, it would help to understand network design and deployment based on an IPv6 environment through IPv6 planning and operations for the end-user perspective such as success or failure of connection on IPv6 migration, exploration of an OSPFv3 routing circuit based on an end-to-end IPv6 environment, and a ping experiment for IPv4/IPv6 dual-stack networks and IPv6 network for OSPFv3 routing. We were able to observe an optimal route for modeling of an end-to-end virtual network through simulation results as well as find what appeared to be a fast ping response time VC server to ensure Internet quality of service better than an HTTP server.

26GHz 40nm CMOS Wideband Variable Gain Amplifier Design for Automotive Radar (차량용 레이더를 위한 26GHz 40nm CMOS 광대역 가변 이득 증폭기 설계)

  • Choi, Han-Woong;Choi, Sun-Kyu;Lee, Eun-Gyu;Lee, Jae-Eun;Lim, Jeong-Taek;Lee, Kyeong-Kyeok;Song, Jae-Hyeok;Kim, Sang-Hyo;Kim, Choul-Young
    • Journal of IKEEE
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    • v.22 no.2
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    • pp.408-412
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    • 2018
  • In this paper, a 26GHz variable gain amplifier fabricated using a 40nm CMOS process is studied. In the case of an automobile radar using 79 GHz, it is advantageous in designing and driving to drive down to a low frequency band or to use a low frequency band before up conversion rather than designing and matching the entire circuit to 79 GHz in terms of frequency characteristics. In the case of a Phased Array System that uses time delay through TTD (True Time Delay) in practice, down conversion to a lower frequency is advantageous in realizing a real time delay and reducing errors. For a VGA (Variable Gain Amplifier) operating in the 26GHz frequency band that is 1/3 of the frequency of 79GHz, VDD : 1V, Bias 0.95V, S11 is designed to be <-9.8dB (Mea. High gain mode) and S22 < (Mea. high gain mode), Gain: 2.69dB (Mea. high gain mode), and P1dB: -15 dBm (Mea. high gain mode). In low gain mode, S11 is <-3.3dB (Mea. Low gain mode), S22 <-8.6dB (Mea. low gain mode), Gain: 0dB (Mea. low gain mode), P1dB: -21dBm (Mea. Low gain mode).

Design of DVB-T/H SiP using IC-embedded PCB Process (IC-임베디드 PCB 공정을 사용한 DVB-T/H SiP 설계)

  • Lee, Tae-Heon;Lee, Jang-Hoon;Yoon, Young-Min;Choi, Seog-Moon;Kim, Chang-Gyun;Song, In-Chae;Kim, Boo-Gyoun;Wee, Jae-Kyung
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.9
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    • pp.14-23
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    • 2010
  • This paper reports the fabrication of a DVB-T/H System in Package (SiP) that is able to receive and process the DVB-T/H signal. The DVB-T/H is the European telecommunication standard for Digital Video Broadcasting (DVB). An IC-embedded Printed Circuit Board (PCB) process, interpose a chip between PCB layers, has applied to the DVB-T/H SiP. The chip inserted in DVB-T/H SiP is the System on Chip (SoC) for mobile TV. It is comprised of a RF block for DVB-T/H RF signal and a digital block to convert received signal to digital signal for an application processor. To operate the DVB-T/H IC, a 3MHz DC-DC converter and LDO are on the DVB-T/H SiP. And a 38.4MHz crystal is used as a clock source. The fabricated DVB-T/H SiP form 4 layers which size is $8mm{\times}8mm$. The DVB-T/H IC is located between 2nd and 3rd layer. According to the result of simulation, the RF signal sensitivity is improved since the layout modification of the ground plane and via. And we confirmed the adjustment of LC value on power transmission is necessary to turn down the noise level in a SiP. Although the size of a DVB-T/H SiP is decreased over 70% than reference module, the power consumption and efficiency is on a par with reference module. The average power consumption is 297mW and the efficiency is 87%. But, the RF signal sensitivity is declined by average 3.8dB. This is caused by the decrease of the RF signal sensitivity which is 2.8dB, because of the noise from the DC-DC converter.

Particle Size Analysis of Lead Aerosol with the use of 2730ppm Lead Nebulizing Solution for Inhalation Toxicology Study (흡입독성 연구를 위한 2730ppm 납 네뷸라이징 용액에서 발생된 에어로졸의 입경분석)

  • Jeung Jae Yeal;Kang Sung Ho;Kim Sam Tae;Lee Eun Kyoung;Song Young Sun;Lee Ki Nam
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.17 no.2
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    • pp.518-524
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    • 2003
  • Ultrasonic nebulizer with the application of new engineering methodology and the design of electronic circuit was made for lead inhalation toxicology study and 2730ppm lead nebulizing solution was used to generate lead aerosol. After modification of source and inlet temperatures, the results of particle size analysis for lead aerosol were as following. The highest particle counting for source temperature 20℃ was 39933.66 in inlet temperature 100℃ and particle diameter 0.75tLm. The highest particle counting for source temperature 50℃ was 39992.71 in inlet temperature 250℃ and particle diameter 0.75μm. The highest particle counting for source temperature 70℃ was 37569.55 in inlet temperature 50℃ and particle diameter 0.75μm. The ranges of geometric mean diameter(GMD) were 0.754-0.784μm for source temperature 2℃, 0.758-0.852μm for source temperature 50℃, and 0.869-1.060μm for source temperature 70℃. The smallest GMD was 0.754μm in source temperature 20℃ and inlet temperature 20℃, and the largest GMD was 1.060μm in source temperature 70℃ and inlet temperature 250℃. The ranges of geometric standard deviation(GSD) were 1.730-1.782 for source temperature 20℃, 1.734-1.894 for source temperature 50℃, and 1.921-2.148 for source temperature 70℃. The lowest GSD was 1.730 in source temperature 20℃ and inlet temperature 20℃, and the highest GSD was 2.148 in source temperature 70℃ and inlet temperature 250℃. Lead aerosol generated in this study was polydisperse. The ranges of mass median diameter(MMD) were 1.856-2.133μm for source temperature 20℃, 1.877-2.894μm for source temperature 50℃, and 3.120-6.109μm for source temperature 70℃. The smallest MMD was 1.856μm in source temperature 20℃ and inlet temperature 20℃, and the largest MMD was 6.109μm in source temperature 70℃ and inlet temperature 250℃. Slight increases for GMD, GSD, and MMD values were observed with same source temperature and increase of inlet temperature. MMD for inhalation toxicology testing in EPA guidance is less than 4μm. In this study, source temperature 20℃ and 50℃ with inlet temperature from 20℃ to 250℃ were conformed to the EPA guidance, but inlet temperature 20℃ and 50℃ for source temperature 70℃ were conformed EPA guidance. MMD for inhalation toxicology testing in OECD and EU is less than 3μm. In this study, source temperature 20℃ and 50℃ with inlet temperature from 20℃ to 250℃ were conformed to the EPA guidance, but none for source temperature 70℃.

Correlations of Cerebellar Function with Psychotic Symptoms and Cognitive Function in Schizophrenic Patients (남자 정신분열병 환자의 소뇌기능과 정신증상 및 인지기능간의 연관성)

  • Kim, Seo Young;Jun, Yong Ho;Kwon, Young Joon;Jeong, Hee Yeon;Hwang, Bo Young;Shim, Se Hoon
    • Korean Journal of Biological Psychiatry
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    • v.14 no.3
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    • pp.184-193
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    • 2007
  • Objectives:There is increasing evidence that the cerebellum plays an important role in cognition and psychiatric symptoms as well as motor coordination. The concept of cognitive dysmetria has been making cerebellar function in schizophrenia the focus of current studies. In other words, disruption in the corticocerebellum-thalamic -cortical circuit could lead to disordered cognition and clinical symptoms of schizophrenia. The purposes of this study were to determine cerebellar dysfunction in male schizophrenic patients semiquantitatively with ICARS and to investigate the clinical and cognitive correlates of ICARS in patients. Methods:We compared the scores of cerebellar neurologic sign using ICARS in 47 male patients with a DSM-IV-TR diagnosis of schizophrenia with 30 gender and age-matched healthy control subjects. The semiquantitative 100-point ICARS consists of 19 items divided into 4 unequally weighted subscores:posture and gait disturbances, kinetic functions, speech disorders and oculomotor disorders. All subjects were also assessed with cognitive function test. Cognitive functions were evaluated by Korean-Mini Mental Status Examination (K-MMSE), Verbal fluency test, and Clock drawing test. The patients were administered Korea version of Positive and Negative Symptom Scale(K-PANSS) to assess the symptom severity. Results:Schizophrenic patients had significantly higher scores on the ICARS than control subjects with posture and gait disturbances, kinetic functions, and oculomotor disorders. They also showed more significant impairments in cognitive function tests than control subjects. There was a significant correlation between ICARS and negative symptoms of patients. In cognitive function test, Clock drawing test was significantly associated with negative symptoms. In addition, Clock drawing test was negatively correlated with the total score of ICARS. Conclusion:In this study, we confirmed that schizophrenic patients have significant impairments in cognitive and cerebellar function, and that those were related with negative symptoms of schizophrenic patients. These results support a role of the cerebellum in schizophrenia. It is meaningful that we used a structured, and reliable procedure for rating neurological soft signs, ICARS. We hope that future prospective studies using a similar design help that rate of neurological sign should have been visible with the progression of illness.

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Developed an output device for high-frequency cosmetic medical equipment using micro multi-needle (마이크로 멀티니들을 이용한 고주파 피부미용 의료기기를 위한 출력 장치 개발)

  • Kim, Jun-tae;Joo, Kyu-tai;Cha, Eun Jong;Kim, Myung-mi;Jeong, Jin-hyoung
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.14 no.5
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    • pp.394-402
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    • 2021
  • The entry of an aging society and the extension of human life expectancy, the increasing interest in women's social advancement and men's appearance, and the natural interest in K-culture through media media, while receiving worldwide attention, Focus on K-Bueaty. Recently, looking at the occupation of the medical tourism field, in the case of aesthetic medicine tourism such as molding and dermatology, it has gained popularity not only in Asia such as China and Japan, but also in North America and Europe. The first external confirmation of human aging is the wrinkles on the skin of the face. Clean, wrinkle-free, elastic and healthy skin is a desire of most people. Skin condition and condition such as focused ultrasonic stimulation (HIFU: High Intensity Focused Utrasound) and low frequency, high frequency (RF: Radio Frequency), galvanic therapy using microcurrent, cryotherapy using rapid cooling, etc. Depending on the method of management, the effect of the treatment differs depending on the output and the stimulation site, etc., even in the treatment of medical equipment and beauty equipment using the same mechanism. In this research, in order to develop invasive high-frequency dermatological devices using a large number of beauty medical devices and microneedles of beauty devices, the international standards IEC 60601-2 (standards for individual medical devices) and MFDS (Ministry of) We designed and developed a high-frequency output device in compliance with the high-frequency stimulation standard announced in the Food and Drug Safety (Ministry of Food and Drug Safety). The circuit design consists of an amplifier (AMP: Amplifier) using Class-A Topology and a power supply device using Half-Bridge Topology. As a result of measuring the developed high-frequency output device, an average efficiency of 63.86% was obtained, and the maximum output was measured at 116.7W and 50.67dBm.

Stand-alone Real-time Healthcare Monitoring Driven by Integration of Both Triboelectric and Electro-magnetic Effects (실시간 헬스케어 모니터링의 독립 구동을 위한 접촉대전 발전과 전자기 발전 원리의 융합)

  • Cho, Sumin;Joung, Yoonsu;Kim, Hyeonsu;Park, Minseok;Lee, Donghan;Kam, Dongik;Jang, Sunmin;Ra, Yoonsang;Cha, Kyoung Je;Kim, Hyung Woo;Seo, Kyoung Duck;Choi, Dongwhi
    • Korean Chemical Engineering Research
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    • v.60 no.1
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    • pp.86-92
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    • 2022
  • Recently, the bio-healthcare market is enlarging worldwide due to various reasons such as the COVID-19 pandemic. Among them, biometric measurement and analysis technology are expected to bring about future technological innovation and socio-economic ripple effect. Existing systems require a large-capacity battery to drive signal processing, wireless transmission part, and an operating system in the process. However, due to the limitation of the battery capacity, it causes a spatio-temporal limitation on the use of the device. This limitation can act as a cause for the disconnection of data required for the user's health care monitoring, so it is one of the major obstacles of the health care device. In this study, we report the concept of a standalone healthcare monitoring module, which is based on both triboelectric effects and electromagnetic effects, by converting biomechanical energy into suitable electric energy. The proposed system can be operated independently without an external power source. In particular, the wireless foot pressure measurement monitoring system, which is rationally designed triboelectric sensor (TES), can recognize the user's walking habits through foot pressure measurement. By applying the triboelectric effects to the contact-separation behavior that occurs during walking, an effective foot pressure sensor was made, the performance of the sensor was verified through an electrical output signal according to the pressure, and its dynamic behavior is measured through a signal processing circuit using a capacitor. In addition, the biomechanical energy dissipated during walking is harvested as electrical energy by using the electromagnetic induction effect to be used as a power source for wireless transmission and signal processing. Therefore, the proposed system has a great potential to reduce the inconvenience of charging caused by limited battery capacity and to overcome the problem of data disconnection.

A Study on the Connectivity Modeling Considering the Habitat and Movement Characteristics of Wild Boars (Sus scrofa) (멧돼지(Sus scrofa) 서식지 및 이동 특성을 고려한 연결성 모델링 연구)

  • Lee, Hyun-Jung;Kim, Whee-Moon;Kim, Kyeong-Tae;Jeong, Seung-Gyu;Kim, Yu-Jin;Lee, Kyung Jin;Kim, Ho Gul;Park, Chan;Song, Won-Kyong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.25 no.4
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    • pp.33-47
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    • 2022
  • Wild boars(Sus scrofa) are expanding their range of behavior as their habitats change. Appearing in urban centers and private houses, it caused various social problems, including damage to crops. In order to prevent damage and effectively manage wild boars, there is a need for ecological research considering the characteristics and movement characteristics of wild boars. The purpose of this study is to analyze home range and identify land cover types in key areas through tracking wild boars, and to predict the movement connectivity of wild boars in consideration of previous studies and their preferred land use characteristics. In this study, from January to June 2021, four wild boars were captured and tracked in Jinju city, Gyeongsangnam-do, and the preferred land cover type of wild boars was identified based on the MCP 100%, KDE 95%, and KDE 50% results. As a result of the analysis of the home range for each individual, it was found that 100% of MCP was about 0.68km2, 2.77km2, 2.42km2, and 0.16km2, and the three individuals overlapped the home range, refraining from habitat movement and staying in the preferred area. The core areas were analyzed as about 0.55km2, 2.05km2, 0.82km2, and 0.14km2 with KDE 95%., and about 0.011km2, 0.033km2, 0.004km2, and 0.003km2 with KDE 50%. When the preferred land cover type of wild boar was confirmed based on the results of analysis of the total home range area and core area that combined all individuals, forests were 55.49% (MCP 100%), 54.00% (KDE 95%), 77.69% (KDE 50%), respectively, with the highest ratio, and the urbanization area, grassland, and agricultural area were relatively high. A connectivity scenario was constructed in which the ratio of the land cover type preferred by the analyzed wild boar was reflected as a weight for the resistance value of the connectivity analysis, and this was compared with the connectivity evaluation results analyzed based on previous studies and wild boar characteristics. When the current density values for the wild boar movement data were compared, the average value of the existing scenario was 2.76, the minimum 1.12, and the maximum 4.36, and the weighted scenario had an average value of 2.84, the minimum 0.96, and the maximum 4.65. It was confirmed that, on average, the probability of movement predictability was about 2.90% better even though the weighted scenario had movement restrictions due to large resistance values. It is expected that the identification of the movement route through the movement connectivity analysis of wild boars can be suggested as an alternative to prevent damage by predicting the point of appearance. In the future, when analyzing the connectivity of species including wild boar, it is judged that it will be effective to use movement data on actual species.