• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2011년도 춘계학술대회 논문집
• /
• pp.427-428
• /
• 2011

• The Journal of Korean Institute of Communications and Information Sciences
• /
• 제30권5C호
• /
• pp.355-363
• /
• 2005

This paper is discussed about the technology of the performance enhancement in the wireless communication between indoor and outdoor environments. In the outdoor wireless communication, the signal has mainly a severe degradation by the fading effect of channel, but that problem may be overcome by using ordinary multiple antenna technology and array signal processing algorithm. Hence, since the channel has the characteristics of both fading and angle spread in the wireless communication between indoor and outdoor, the ordinary technology cannot solve the signal degradation due to the angle spread. In order to solve the problem, in this paper, the characteristic of the wireless channel between indoor and outdoor is first analyzed and considered the channel models fit to that case. We propose the new multiple antenna algorithm by use of mean steering vector concept, and obtained the results of the performance enhancement. With the results of the performance analyses through of the numerical study and computer simulation, we show that the proposed algorithm has more enhanced signal to noise ratio than the previous algorithm.

• Journal of the Korean Institute of Landscape Architecture
• /
• 제30권3호
• /
• pp.57-63
• /
• 2002

This landscape design was proposed for the Buchon Special School Competition, held by the Kyonggi Province Office of Education. The authors collaborated on this design and won first prize in November of 2001. In the design proposal, on the basis of the knowledge of; mentally retarded children the children's activities, nature and health, and the healing gardens, the special school outdoor spaces were designed to meet the particular needs of the users. The school outdoor spaces are design for various types of users-children, adolescents, parents, siblings, staff, volunteers and visitors. The following are some of the basis concerns in the design of the school outdoor spaces : garden site planning, garden location, security, microclimate, entering and exiting, accessibility, usability, user group territories, supervision, attracting trained volunteers, a range of high-quality social settings, accommodation of different student types, accommodation of needs for both challenge and rest, child nature interaction, diversity of natural settings, hands-on activity, integrating the arts, and maintenance. The following are some of the major features in the design of school outdoor spaces : pleasant and inviting entry areas, sports grounds with different levels of challenge, gardens with plants having strong fragrances and/or tactile qualities, resting places with many types and forms of seating and weather-mitigating features, play grounds for all student types, roof gardens for users to experience nature in man-made environments, and walkways and winding paths with various trees, shrubs and flowers. In the special school outdoor spaces, people would perceive a unique sense of place through the various types of spaces and features described above. An example of the true meaning of a playing and resting place and a restorative and therapeutic environment is provided in the school outdoor spaces.

• Corrosion Science and Technology
• /
• 제18권3호
• /
• pp.86-91
• /
• 2019

Generally, atmospheric corrosion is the electrochemical degradation of metal that can be caused by various corrosion factors of atmospheric components and weather, as well as air pollutants. Specifically, moisture and particles of sea salt and sulfur dioxide are major factors in atmospheric corrosion. Using galvanized steel is one of the most efficient ways to protect iron from corrosion by zinc plating on the surface of the iron. Galvanized steel is widely used in automobiles, building structures, roofing, and other industrial structures due to their high corrosion resistance relative to iron. The atmospheric corrosion of galvanized steel shows complex corrosion behavior, depending on the plating, coating thickness, atmospheric environment, and air pollutants. In addition, corrosion products are produced in different types of environments. The lifespans of galvanized steels may vary depending on the use environment. Therefore, this study investigated the corrosion behavior of galvannealed steel under atmospheric corrosion in two locations in Korea, and the lifespan prediction of galvannealed steel in rural and coastal environments was conducted by means of the potentiostatic dissolution test and the chemical cyclic corrosion test.

• Journal of KIISE
• /
• 제44권7호
• /
• pp.733-741
• /
• 2017

LPWAN(Low Power Wide Area Network) technology is M2M (Machine to Machine) networking technology for the Internet of Things. The technology is designed to support low-power, long-distance and low-speed communications that are typical of LoRaWAN(Long Range Wide Area Network). To exchange inter-object information using a LoRaWAN, the link performances for various environments must be known. however, active performance analysis research that is based on an empirical environment is nonexistent. Therefore, this paper empirically evaluates the performance of the LoRa (Long Range) link, a physical communication technology of the LoRaWAN for various variables that may affect the link quality in indoor and outdoor environments. To achieve this, a physical performance monitoring system was designed and implemented. A communication experiment environment was subsequently constructed based on the indoor and outdoor conditions. The SNR(Signal to Noise Ratio), RSSI(Received Signal Strength Indication), and the PDR(Packet Delivery Ratio) were evaluated.

• Journal of Korean Society for Atmospheric Environment
• /
• 제17권2호
• /
• pp.193-201
• /
• 2001

Acidic air pollutants were collected to characterize indoor air quality in a residential area in the summer. All indoor and outdoor samples were measured simultaneously using an annular denuder system(ADS) in Seoul. The data set was collected from July 26 to September 11, 1997. The mean indoor/outdoor ratios measured from this study were : 0.34 for $HNO_3$; 0.91 for $HNO_2$; 0.22 for $SO_2$; 1.34 for $NH_3$; 0.78 for $PM_{2.5}(d_p$ <2.5 $mutextrm{m}$); 0.90 for $SO_{4}^{2-}$; 0.68 for $NO_{3}^{-}$ and 0.79 for $NH_{4}^{+}$. Indoor concentrations of $HNO_3$, $SO_2$ and $PM_{2.5}$ were highly correlated with the outdoor concentrations. The relationship between indoor and outdoor air is dependent, to a large extent, on the rate of air exchange between these two environments. A tracer-gas decay technique with sulfur hexafluoride ($SF_{6}$) as a tracer gas was used to estimate the air exchange of a private home in the summer. The average air exchange rate was estimated to be 23.7 hr(sup)-1. The deposition velocities for $SO_{4}^{2-}$, $NO_{3}^{-}$ and $NH_{4}^{+}$ calculated were 0.17, 0.69 abd 0.39 cm/sec, respectively.

• Journal of Environmental Science International
• /
• 제12권9호
• /
• pp.967-976
• /
• 2003

Volatile organic compounds (VOCs) are present in essentially all natural and synthetic materials from petrol to flowers. In this study, indoor and outdoor VOCs concentrations of houses, offices and internet-cafes were measured and compared simultaneously with personal exposures of each 50 participants in Asan and Seoul, respectively. Also, factors that influence personal VOCs exposure were statistically analyzed using questionnaires in relation to house characteristics, time activities, and health effects. All VOCs concentrations were measured by OVM passive samplers (3M) and analyzed with GC/MS. Target pollutants among VOCs were Toluene, o-Xylene, m/p-Xylene, Ethylbenzene, MIBK, n-Octane, Styrene, Trichloroethylene, and 1,2-Dichlorobenzene. Indoor and outdoor VOCs concentrations measured in Seoul were significantly higher than those in Asan except Ethylbenzene. Residential indoor/outdoor (I/O) ratios for all target compounds ranged from 0.94 to 1.51 and I/O ratios of Asan were a little higher than those of Seoul. Relationship between personal VOCs exposure, and indoor and outdoor VOCs concentrations suggested that time-activity pattern could affect the high exposure to air pollutant. Factors that influence indoor VOCs level and personal exposure with regard to house characteristics in houses were building age, inside smoking and house type. In addition insecticide and cosmetics interestingly affected the VOCs personal exposure. Higher exposure to VOCs might be caused to be exciting increase and memory reduction, considering the relationship between measured VOCs concentrations and questionnaire (p<0.05).

• Journal of the Korean Home Economics Association
• /
• 제41권2호
• /
• pp.141-153
• /
• 2003

The purpose of this study was to analyze and determine the level of the satisfaction and awareness of facilities in child care centers among teachers and parents. Special attention was given to both the indoor and outdoor environments from the viewpoints of both parents and teachers. The subject of this research focused on parents who leave their children at child care centers, and teachers who work for the center. The data was compiled by performing both T-tests and paired T-test. The information was processed by a program called SPSS WIN 10.0. The results were as follows ; 1. (a) With regard to the satisfaction of the external and internal facilities : It was determined that both the play rooms and the wall-pattern arrangements were satisfactory to both the parents and the teachers. (b) Regarding the awareness of the importance of facilities, while the parents focused more on the play rooms and the external environments, the teachers placed more importance on the bathrooms and the play rooms. 2. In the paired T-test that determined whether their individual opinions were different in terms of the satisfaction and awareness of facilities, it was interesting to see that both the parents and the teachers showed significant differences in their opinions and priorities about the porches, the play rooms, the bathrooms and the wall-pattern arrangements. In general, their awareness was much higher than the satisfaction with these facilities. 3. In the T-test that determined whether there were any tendencies in the satisfaction and awareness respectively in the two groups, the satisfaction rate was higher among the parents than the teachers. In terms of the awareness of the importance of the facilities, the teachers rated the bathrooms and the wall-pattern arrangements as a priority.

• Journal of Korean Society of Steel Construction
• /
• 제29권3호
• /
• pp.193-204
• /
• 2017

Fatigue strength of temporary steels and painted structural steels corroded under outdoor atmospheric environments is not clear. In this study, fatigue tests were carried out on steel plates which were cut off from 7-year-old temporary structural member under subway construction environment and from 75-year-old Yeongdo bridge member under marine atmospheric environment. After removing corrosion production on the steel surface, 3-dimensional surface geometry of the corroded steel was measured at intervals of $1.0{\times}1.0mm$, and corrosion characteristics such as minimum, maximum and mean values of residual thicknesses were calculated. From the fatigue test and FEM analysis results, the relationship between corrosion characteristics and fatigue behavior was presented, and change in fatigue strength of the unpainted and painted steels corroded in outdoor environments was also presented.

• Korean Journal of Veterinary Service
• /
• 제32권4호
• /
• pp.385-389
• /
• 2009

This study was attempted to survey on the prevalence of canine heartworm infection (Dirofilaria immitis) in the Incheon area in 2006. This study showed comparative infection rates of canine heartworm in conjunction with different geographic locations and rearing environments (i.e., indoor, outdoor or free roaming). In total, 24 dogs (6.0%) were D. immitis positive among a total of 400 tested dogs. The geographic distribution of detection rates was Nam-gu (2 dogs, 6.7%), Yeonsu-gu (1 dog, 3.0%), Namdonggu (5 dogs, 8.0%), Pupyoung-gu (4 dogs, 6.7%), Kanghwa-gun (8 dogs, 13.0%), and Onjin-gun (4 dogs, 11.1%). In addition, 4 dogs (2.0%) or 20 dogs (10.0%) were positive for D. immitis among 202 indoor dogs or 198 outdoor dogs including free roaming dogs, respectively, while 13 dogs (11.7%) were positive for D. immitis among 111 outdoor dogs excluding free roaming dogs. In the case of 87 free roaming dogs, 7 dogs (8.1%) among them were positive for D. immitis.