• Journal of the Korean Institute of Gas
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• v.5 no.1
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• pp.29-36
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• 2001

The permeation properties of $O_2\;and\;N_2$ were measured for bromobisphenol A polysulfone(BPSf), bisphenol A trimethylsilylated polysulfone(TMSPSf) and their blend membrane to investigate the structure-properties relationships. BPSf shows relatively high permselectivity. It can be explained that the strong polarity of bromine in BPSf increases chain packing ability. In this case the distance of polymer chains is reduced by increasing of interchain interaction by induced dipole. TMSPSf shows relatively high permeability. The higher value of permeability coefficients for TMSPSf is due to the substitution of very bulky trimethylsilyl groups. The replacement of phenyl hydrogens of bisphenol A polysulfone(PSf) with trimethylsilyl groups results in higher fractional free volume(FFV). In this work, taking into account the complimentary features of BPSf and TMSPSf, BPSf/TMSPSf blend was prepared and the compatibility in mixing are examined. The BPSf/TMSPSf blend shows higher permeability than commercial PSf, with minimum loss of selectivity. The miscibility of the BPSf/TMSPSf blend is confirmed by the single glass transition temperature.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.5
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• pp.910-920
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• 2016

This study is to understand the problems of current police raincoats for professional policemen and conscripted policemen. Interviews and a survey were completed to investigate the wearing conditions of current police raincoats. The questionnaire was composed of questions on current wearing conditions of raincoat, motional adaptability, dimensional compatibility, design suitability and demographic information on the research target. The results indicated that the wearing frequency of raincoats had significant difference according to duty and age range. The main reason for the low wearing frequency was the uncomfortableness of working while wearing the raincoat, followed by the inconvenience of managing the raincoat after use and feeling hot while wearing the raincoat. The three most important factors when wearing a raincoat was pleasantness, activity capability and the functionality of the fabric. The satisfaction on body parts during motions tended to be evaluated lower as the raincoat size increased. The results of the dissatisfaction factors indicated that the raincoat hood had the most problems. There was inconvenience when using the equipment belt because officers have to wear their belts inside the raincoat. In regards to the fabric satisfaction level, respondents were less satisfied with ventilation, hygroscopicity, and drying time. Therefor it appeared that the current raincoat had problems due a lack of functionality in regards to ventilation, hygroscopicity, and quick drying; in addition, the satisfaction on motional adaptability had a significant difference according to raincoat size.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.991-1013
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• 2020

E-health services have provided interoperability between personal health devices in personal area network, based the ISO/IEEE 11073 standard. In the healthcare system, the manager handles most agents concurrently through wireless communication. However, due to the distance limitation and the increased number of agents, it may be difficult to provide continuous connectivity. Recently, body area devices have been equipped with various applicable agents, which can even handle agents on behalf of the manager. A BAD may act as an intermediary device to increase system efficiency and performance. In this study, a device called "proxy", which can be installed as software on BAD devices, is proposed. The data measured by an agent can be sent to the proxy first, and subsequently be sent to the manager again. Agents and the manager are not aware of the proxy existence and work normally without the proxy. Furthermore, a new smart proxy and modified manager are proposed. The smart proxy acts as one agent handling measurement data from several agents, which can transmit a significant amount of data at once. The proxy and smart proxy maintain compatibility with existing devices that conform to the 20601 standard. The proposed schemes are verified and the complexities of devices are analyzed. The analysis shows no significant difference among the proxy, smart proxy, and manager. Simulations exhibit that the proposed schemes can improve the system performance.

• Electronics and Telecommunications Trends
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• v.38 no.1
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• pp.55-64
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• 2023

Recently, preparations for 6G have led to the increasing interest in integrated or hybrid communication networks considering low-orbit satellite communication networks with terrestrial mobile communication networks. In addition, the demand for frequency allocation for new mobile services from low-orbit small satellites to provide global internet of things (IoT) services is increasing. The operation of such satellites and terrestrial mobile communication networks may inevitably cause interference in adjacent bands and the same band frequency between satellites and terrestrial systems. Focusing on the results of the recent ITU-R WP4C meeting, this study introduces the current status of frequency sharing and interference issues between satellites and terrestrial systems, and frequency allocation issues for new mobile satellite operations. Coexistence and compatibility studies with terrestrial IMT in L band and 2.6 GHz band, operated by Inmassat and India, respectively, and a new frequency allocation study (WRC-23 AI 1.18) are carried out to reflect satellite IoT demand. For the L band, technical requirements have been developed for emission from IMT devices at 1,492 MHz to 1,518 MHz to bands above 1,518 MHz. Related studies in the 2 GHz and 2.6 GHz bands are not discussed due to lack of contributions at the recent meeting. In particular, concerning the WRC-23 agenda 1.18 study on the new frequency allocation method of narrowband mobile satellite work in the Region 1 candidate band 2,010 MHz to 2,025 MHz, Region 2 candidate bands 1,695 MHz to 1,710 MHz, 3,300 MHz to 3,315 MHz, and 3,385 MHz to 3,400 MHz, ITU-R results show no new frequency allocation to narrow mobile satellite services. Given the expected various collaborations between satellites and the terrestrial component are in the future, interference issues between terrestrial IMT and mobile satellite services are similarly expected to continuously increase. Therefore, participation in related studies at ITU-R WP4C and active response to protect terrestrial IMT are necessary to protect domestic radio resources and secure additional frequencies reflecting satellite service use plans.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.249-255
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• 2015

In this study, through the additional information of the PET / CT images by utilizing the basic data of TPS clinical application on the basis of the image re-forming synthetic function, the True-D technology and MIM software for continued research and development in combination, based on the combination-work between the respective images, reducing the time and cost of useful reading in clinical wide use of image width, efficient, effective tool for tumor targeting at diagnosis and radiation therapy by use as, by using the precise therapeutic effect determination, the time taken to read in the clinical, unnecessary and expect to a can reduce the additional examination by the creation of tumor patients read reports and PACS such asWe expect to be utilized for compatibility development with other software to evaluate the performance of PET / CT equipment.

• Journal of Astronomy and Space Sciences
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• v.27 no.2
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• pp.107-116
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• 2010

We developed the playback control software for a high-speed playback system which is a component of the Korea-Japan Joint VLBI Correlator (KJJVC). The Mark5B system, which is a recorder and playback system used in the Korean VLBI Network (KVN), has two kinds of operation mode. That is to say, the station unit (SU) mode, which is for the present Mark4 system, and the VSI mode, which is for the new VLBI standard interface (VSI) system. The software for SU is already developed and widely used in the Mark4 type VLBI system, but the software for VSI has only been developed for recording. The new VLBI system is designed with a VSI interface for compatibility between different systems. Therefore, the playback control software development of the VSI mode is needed for KVN. In this work, we developed the playback control software of the Mark5B VSI mode. The developed playback control software consists of an application part for data playing back, a data input/output part for the VSI board, a module for the StreamStor RAID board, and a user interface part, including an observation time control part. To verify the performance of developed playback control software, the playback and correlation experiments were performed using the real observation data in Mark5B system and KJJVC. To check the observation time control, the data playback experiment was performed between the Mark5B and Raw VLBI Data Buffer (RVDB) systems. Through the experimental results, we confirmed the performance of developed playback control software in the Mark5B VSI mode.

• Journal of Korea Multimedia Society
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• v.17 no.11
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• pp.1313-1324
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• 2014

Korea has high quality level of ICT Technologies, however it still have a long way to go before invigoration of ICT in agriculture industry. The government of Korea supply to agriculture ICT systems, however these are the enclosed type and insufficient the level of connectivity, compatibility, and integrity between ICT systems. Farmers can not share crop information and one system can not use with others in combination. Recently, IoT(Internet of Things) become popular to emphasize the vision of a global internet and ICT industry. The IoT is a critical technology that leads future internet generation. We believe that IoT will change status of agriculture industry and appearance of various agriculture business model. Using IoT technology is provided a platform of opportunities to optimize work processes and efficient use of energy, time and labour in farm. It can automatically control temperature, humidity, sunshine system and so on for optimal growth conditions at greenhouse and plant factory. Growth setting can even be controlled and monitored crop condition and disease by a smartphone app or PC. It is possible to improve quality of farming and farm product. We suggest that construction of IoT platform through open API in agriculture industry.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.3
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• pp.156-162
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• 2001

In order to monitor local climatic information, twelve automated weather stations (AWS) were installed in alpine area by the Alpine Agricultural Experiment Station, Rural Development Administration (RDA), at the field of major crop located in around highland area, and collected data from 1993 to 2000. Hourly measurements of air and soil temperature (underground 10 cm,20 cm), relative humidity, wind speed and direction, precipitation, solar radiation and leaf wetness were automatically performed and the data could be collected through a public phone line. Datalogger was selected as CR10X (Campbell scientific, LTD, USA) out of consideration for sensers' compatibility, economics, endurance and conveniences. All AWS in alpine area were combined for net work and daily climatic data were analyzed in text and graphic file by program (Chumsungdae, LTD) on 1 km $\times$ 1 km grid tell basis. In this analysis system, important multi-functionalities, monitoring and analysis of local climatic information in alpine area was emphasized. The first objective was to obtain the output of a real time data from AWS. Secondly, daily climatic normals for each grid tell were calculated from geo-statistical relationships based on the climatic records of existing weather stations as well as their topographical informations. On 1 km $\times$ 1 km grid cell basis, real time climatic data from the automated weather stations and daily climatic normals were analyzed and graphed. In the future, if several simulation models were developed and connected with this system it would be possible to precisely forecast crop growth and yield or plant disease and pest by using climatic information in alpine area.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5375-5400
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• 2016

IOMMU is a hardware unit that is indispensable for DMA. Besides address translation and remapping, it also provides I/O virtual address space isolation among devices and memory access control on DMA transactions. However, currently commodity virtualization platforms lack of IOMMU virtualization, so that the virtual machines are vulnerable to DMA security threats. Previous works focus only on DMA security problem of directly assigned devices. Moreover, these solutions either introduce significant overhead or require modifications on the guest OS to optimize performance, and none can achieve high I/O efficiency and good compatibility with the guest OS simultaneously, which are both necessary for production environments. However, for simulated virtual devices the DMA security problem also exists, and previous works cannot solve this problem. The reason behind that is IOMMU circuits on the host do not work for this kind of devices as DMA operations of which are simulated by memory copy of CPU. Motivated by the above observations, we propose an IOMMU para-virtualization solution called PVIOMMU, which provides general functionalities especially DMA security guarantees for both directly assigned devices and simulated devices. The prototype of PVIOMMU is implemented in Qemu/KVM based on the virtio framework and can be dynamically loaded into guest kernel as a module, As a result, modifying and rebuilding guest kernel are not required. In addition, the device model of Qemu is revised to implement DMA access control by separating the device simulator from the address space of the guest virtual machine. Experimental evaluations on three kinds of network devices including Intel I210 (1Gbps), simulated E1000 (1Gbps) and IB ConnectX-3 (40Gbps) show that, PVIOMMU introduces little overhead on DMA transactions, and in general the network I/O performance is close to that in the native KVM implementation without IOMMU virtualization.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.135-141
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• 2015

According to the statistics, occupational fatal injuries by mobile cranes were about 12 per year in whole industrial. Mobile cranes are widely used in various parts of industries to improve the efficiency of the work. However considerable number of fatal injuries happen each year during the operation of the machines. In this study, the current regulations to be adequate in industrial site have to be renew in order to prevent the fatal injuries by mobile cranes. Fatal injury analyses were conducted with several accident cases by the mobile cranes. For each accident, the causes of the injuries were examined and proper safety measures were proposed. In this study, the mobile crane showed a high fatality rate in industrial accidents and no detailed cause analysis of fatal accidents was conducted in terms of unsafe acts or conditions. This study proposed a revision of the standard guideline as an accident prevention measures through in-depth analysis of fatal accidents. First, among the mainly five machines caused the accidents, mobile crane was higher for the second showed 0.6% for number of fatalities compared to number of mobil cranes and for the third showed 11% for number of fatalities compared to number of injuries. Second, main cause of cognitive engineering agenda was visibility, responsibility, affordance. As the measures to prevent accidents before starting operation, alternative revision for the fool proof including visibility, responsibility, affordance etc. for the fool proof measures was proposed. Third, alternative revision as cognitive accident prevention for the fail safe measures was proposed.