• Journal of Radiation Protection and Research
• /
• v.41 no.3
• /
• pp.185-190
• /
• 2016

Background: In order to measure neutron energy spectra, the conventional Bonner Sphere Spectrometers (BSS) are widely used. In this spectrometer, several measurements with different size Bonner spheres are required. Operators should, therefore, place these spheres in several times to a measurement point where radiation dose might be relatively high. In order to reduce this effort, novel neutron energy spectrometer using an onion-like single Bonner sphere was proposed in our group. This Bonner sphere has multiple sensitive spherical shell layers in the single sphere. In this spectrometer, a band-shaped thermal neutron detection medium, which consists of a LiF-ZnS mixed powder scintillator sheet and a wavelength-shifting (WLS) fiber readout, was looped to each sphere at equal angular intervals. Amount of LiF neutron converter is reduced near polar region, where the band-shaped detectors are concentrated, in order to uniform the directional sensitivity. The LiF-ZnS mixed powder has an advantage of extremely high light yield. However, since it is opaque, scintillation photons cannot be collect uniformly. This type of detector shows no characteristic shape in the pulse height spectrum. Subsequently, it is difficult to set the pulse height discrimination level. This issue causes sensitivity fluctuation due to gain instability of photodetectors and/or electric modules. Materials and Methods: In order to solve this problem, we propose to replace the LiF-ZnS mixed powder into a flexible and Transparent RUbber SheeT type $LiCaAlF_6$ (TRUST LiCAF) scintillator. TRUST LiCAF scintillator can show a peak shape corresponding to neutron absorption events in the pulse height spectrum. Results and Discussion: We fabricated the prototype detector with five sensitive layers using TRUST LiCAF scintillator and conducted basic experiments to evaluate the directional uniformity of the sensitivity. Conclusion: The fabricated detector shows excellent directional uniformity of the neutron sensitivity.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.9
• /
• pp.2014-2026
• /
• 1997

In this paper, the performances of wireless asynchronous transfer mode (ATM) cell transmission in mobile work are analyzed. We adopt 16Star QAM as amodulation technique in wireless channel and considered Reed-Solomon, convolutional, and concatenated coding to improve the error rate performances, and also proposed the Partial Concatenated Coding (PCC) technique as UEP(unequal error protection) code for efficient transmission of ATM cell in the air interface. We consider Doppler's effect, Rician fading, and diversity technique of maximal-ratio combining (MRC) for mobile channel model. For performance measure, we analyze bit error rate, ATM cell loss probability, ATM cell error probability, and network performances of ATM cell transmission delay and throughput. The numerical results show that the adoption of PCC is a prospective way for the evolution of future wireless ATM network on mobile environment.

• Journal of Radiation Protection and Research
• /
• v.29 no.3
• /
• pp.173-177
• /
• 2004

The Chinese cabbage, being one of the principal foodstuffs in Asian countries, is tested for iodine exposure. As a radioactive source, iodine-125 of which the radiological half life is 60 days was used to measure the concentration change. Experiments were carried out four times with different times of exposure. The iodine source was prepared by the chemical reaction of NaI in order to avoid producing relatively large iodine which might be generated In the case of crystal evaporation. The deposition velocity was obtained from the integrated air concentration and surface concentration of the Chinese cabbage. The environmental half life was also calculated.

• Journal of the Korean Society for Railway
• /
• v.10 no.1 s.38
• /
• pp.57-66
• /
• 2007

1974. 8. 15 SeoulMetro, beginning with the first electric railway established at six cities, so it is managing mass transportation of traffic. Especially, in case of seoul, It is managing that from one to eight lines, 286.9km, 265 stations have installed and now it is carrying about 5.5million of passengers everyday, and 2,000million passengers a year. So accident is increasing from the station every year. For this measure, SeoulMetro prepares safety fence for passengers crash but, as suicides or people who watch the accident took place, for at the bottom of passengers crash protection, PSD installing is needed. Even though, PSD is managing ATO section but, in controlling SeoulMetro, one to four lines sections are (ATS, ATC)section. Between as ATS, ATC section, ATO section, subway gate and PSD must have opened and crossed always at the time. And the interlock control corrosion protection gate, managing skills with installation, method, using in history, apply to 10rail cars one train sets, and maximum applying 2224% sections of passengers congested that consideration is to be needed. So 2004, SeoulMetro improved technology and basie design of PSD at ATS section. Based on this, from 2005.4 to 2006.6, using subway 2lines per 12stations set the model installation(full type 11stations, half type 1station) After installing in case of success, it is going about to suggest that effective analysis and hereafter subject.

• Journal of the Korea Convergence Society
• /
• v.8 no.9
• /
• pp.41-47
• /
• 2017

This study is a preceding research designed to deduct an institutional supplementary measure that minimizes any inevitable side effects from the improvement of artificial intelligence (AI) technology, which is the core element of the Fourth Industrial Revolution. In this specific case in which the Robo-Advisor, the representative type of AI-applied technology, was hacked by a third party and ended up manipulating prices, the study was intended to examine the responsibility relationship of the current legal framework. Although the current legal framework strictly prohibits acts such as hacking and manipulation, it was confirmed that if the Robo-Advisor management firm acts in compliance with protection measures regarding hacking, the firm is free from any legal liabilities and there is insufficient legal protection available for ordinary investors with grand-scale damage from price manipulation Based on this study, further studies are needed to derive more institutional supplementary measures on overcoming these problems.

• Analytical Science and Technology
• /
• v.25 no.2
• /
• pp.127-132
• /
• 2012

A test tool for self-leveling and flowing characters of coating materials used to semiconductors and electronic parts, especially for protection of LCD and PDP connectors, was designed, and the test tool was evaluated using polymeric siloxane coating materials which have various viscosities. The test results showed that the designed test tool was effective to measure self-leveling and flowing properties of coating materials. Therefore, considering that the viscosity is not directly correlated with self-leveling and flowing properties, we believe that this test tool will be a very useful tool for measurement instead of classical method using viscosities of coating materials. Particularly, the measurement of self-leveling and flowing properties using the test tool would be expected to be used in the area of selecting suitable protective coating materials for LCD (Liquid Crystal Display), PDP (Plasma Display Panel) and semiconductor connection parts.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.16 no.3
• /
• pp.93-100
• /
• 2002

In this paper, in ordor to examine the relevant technical facts which are very instructive to revise the domestic standard for lightning protection systems, standards and technical guideline for the protection of structure against lightning were reviewed, and several issues of the domestic standards were experimentally investigated. As a consequence, the insulator of relatively low implse voltage and a large percentage of lighting rods is flashovered by relatively low impulse voltage and a lage percentage of lighting current flows through supporting mast. Thus the potential gradient in the vicinity of supporter for lighting rods is extremely increased and the role of lighting propection systems is nullified. It seems obvious that the flashover of insular supporting lighting rod can range from erratic operation of microelectronic devices to minor physical ham or even death, or costly damage electrical equipment.

• Journal of radiological science and technology
• /
• v.29 no.2
• /
• pp.93-98
• /
• 2006

Satisfaction of the patient against the medical service in department of radiology and it evaluated the different recognition of radiological technologist and patient. and investigates it's improvement direction. It sent the reply the above the which is a usual result in question result of the most that, the receipt process it was complicated in the portion which is insufficient,"The receipt process is complicated", "waiting time is long"and "don't radiation protection for patient and guardian". Also these a facts was recognizing patients and radiological technologist all. And the effort of the radiological technologist is necessary with the method which reduces a recognition difference. The periodical medical service satisfaction investigates and must endeavor in reform measure preparation.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 1997.11a
• /
• pp.44-48
• /
• 1997

The Swedish Fire Research Board was established in 1979 to initiate and fund relevant fire research efforts. The Board is responsible for a long term research programme revised every third year, and the Board is one of two major Swedish sponsors of all fire research. Beside the Board we also have the Swedish National Rescue Services, funded by the government. BRANDFORSK gives very high priority for the industry and the insurance company and the need they express for fire research. Research that the Rescue Services Board are funding is mainly focusing the need for the fire department. The Swedish Fire Research Board, BRANDFORSK, is the joint agency of the Swedish government, the insurance industry and the business sector, for the initiation, funding and supervision of different kinds of fire research. Work is directed by a Programme Board and is performed in the form of projects at universities, research institutes, state authorities and private firms. The Secretariat of BRANDFORSK shares the premises of the Swedish Fire Protection Association, SFPA, and the SFPA is the principal and the party which enters into agreement with the State. The programme for the period 1997-1999 has been drawn up on the basis of both damage development and the trends in society which can be noted, and the evident fire problems of the interested parties and their need for fire research. The inputs in the programme have been broken down seven problem areas. In every problem area different project areas are set out, and these primarily specify the aim of the work. Our seven problem-areas are; Costs and benefits of fire protection measure. The role and behaviour of people and organizations Fire In buildings Fire in underground facilities Rescue operations fire in industries Fire and the environment. In comparison with previous fire research programmes, cost/benefit studies have been accorded higher priority, and this is also reflected in other problem areas. Grater Emphasis

• Journal of Radiation Protection and Research
• /
• v.13 no.2
• /
• pp.57-66
• /
• 1988

A series of experiments is performed to measure radon concentration in the near-surface soil gas at the four locations (Cheju-Si, Seoguipo-Si, Taejeong-eup, Seongsan-eup) in Cheju Island, using CR-39 detectors placed inside radon cups. Two types of radon cups are installed in shallow holes of about 15 cm in diameter and 50cm in depth. The optimum etching conditions, i.e., the concentration of NaOH solution, etchant temperature and etching time, are found to be 625N, $70^{\circ}C$ and 5.5 hours for CR-39 detectors. A typical conversion factor of radon cup is calculated as $$1track/mm^3{\cdot}30day=0.059Bq/{\ell}$$. Average radon concentrations over 30 days measured in Cheju Island from May 1, 1987 to April 23, 1988 are $3.1{\pm}0.3Bq/{\ell}$ for open radon cups and $1.7{\pm}0.2Bq/{\ell}$ for closed radon cups.