• The Journal of the Acoustical Society of Korea
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• v.33 no.2
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• pp.126-132
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• 2014

In this paper, a DFSA (Dynamic Framed Slotted ALOHA) based anti-collision algorithm is described and a performance improved algorithm of DFSA and FSA is proposed. The proposed method makes use of expected values and has merits in operation speed by estimating closest value of the number of tags on a single operation. The algorithm compares and analyses number of empty slots and collide slots in accordance with the number of tags, which enables estimation of actual number of tags. we simulated the proposed algorithm and compared it with conventional methods. Results show that our method needs average 18.8 rounds to identify all tags. In case of less than 1000 tags, an average of 18.2 rounds is necessary and an average of 19.2 rounds is needed to identify all tags for more than 1000 tags. The proposed algorithm improves processing speed by 3.1 % comparing to DFSA with cancellation strategy, 10.1 % comparing to DFSA, 37.5 % comparing to FSA(Framed Slotted ALOHA).

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.61-66
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• 2014

As a key technology of U-health, RFID can be applied to the hospitals in a variety of cases such as patient tracking, medical instrument management, and so on. However, adoption of RFID in healthcare does not reach expectations because of huge cost. Exact estimation of cost and effectiveness will boost adoption of RFID in healthcare. This study proposes a novel simulation technique to evaluate cost and effectiveness of RFID in hospital environment. To do this, this study proposes a technique for modeling patients' movements in a hospital. Based on the model, this study provides how to obtain tag event dataset by means of simulating identifications of RFID tags that are attached to patients.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.120-127
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• 2009

An electric furnace, inside which desired temperatures are kept constant by generating heat, is known to be a difficult system to control and model exactly because system parameters and response delay time vary as the temperature and position are changed. In this study the heating system of ceramic drying furnaces with time-varying parameters is mathematically modeled as a second order system and control parameters are estimated by using a RIV (Recursive Instrumental-Variable) method. A modified bang-bang control with magnitude tuning is proposed in the time optimal temperature control of ceramic drying electric furnaces and its performance is experimentally verified. It is proven that temperature tracking of adaptive time optimal control using a second order model is more stable than the GPCEW (Generalized Predictive Control with Exponential Weight) and rapidly settles down by pre-estimation of the system parameters.

• Korean Journal of Human Ecology
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• v.14 no.4
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• pp.683-692
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• 2005

This study was intended to analyze the clothing shopping orientations and purchasing practices for men's dress shirts. It was conducted by means of convenience sampling survey with male office workers who usually wear dress shirts at work and who also live in Seoul, Geonggi, and Chungcheong area. The data collected were analyzed by frequency analysis, cross-tabulation analysis, factor analysis, t-test, and ANOVA using SPSS. The results are as follows: 1) Clothing shopping orientations were classified into six factors: brand oriented; planned; enjoying; expediency oriented; negative shopping; and low price oriented. There were partially significant differences in clothing shopping orientations according to the surveyees' age. 2) The surveyees prioritized low price and expediency in clothing shopping, but they also showed low interest in brands. 3) The criteria for purchasing were in the order of size, color, comfort, and design. There were also partially significant differences in the estimation criteria for dress shirts according to marital status and age. 4) Most respondents tended to purchase 3 or 4 pieces of dress shirts a year, paying 30,000 to 50,000 won for a piece, usually at department stores. 5) When they purchase a dress shirt, they always considers its size. In the case of married men, however, it is the laundry tag that they do care about.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.45-49
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• 2010

RTLS (Real Time Locating Systems) are used to track and identify the location of objects in real time. RTLS generally consist of tags, readers and engine etc. and applied in various environments. One problem encountered in RTLS is constraints for setting up readers according to environments. In these challenging environments, it is necessary to develop techniques that can use mobile readers. As mobile reader increase, whole reader increase. And it is necessary to develop technique that can select useful readers. Selected readers including mobile readers take effect performance of RTLS. This paper introduces the technique for selecting good readers using the convex hull algorithm. The result show the good performance which based on tag's location error and reduce the networking overhead.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.543-554
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• 2013

Acoustic Doppler Current Profilers (ADCPs) are increasingly popular in the river research and management communities being primarily used for estimation of stream flows. ADCPs capabilities, however, entail additional features that are not fully explored, such as morphological representation of river or reservoir bed based upon multi-beam depth measurements. In addition to flow velocity, ADCP measurements include river bathymetry information through the depth measurements acquired in individual 4 or 5 beams with a given oblique angle. Such sounding capability indicates that multi-beam ADCPs can be utilized as an efficient depth-sounder to be more capable than the conventional single-beam eco-sounders. The paper introduces the post-processing algorithms required to deal with raw ADCP bathymetry measurements including the following aspects: a) correcting the individual beam depths for tilt (pitch and roll); b) filtering outliers using SMART filters; d) transforming the corrected depths into geographical coordinates by UTM conversion; and, e) tag the beam detecting locations with the concurrent GPS information; f) spatial representation in a GIS package. The developed algorithms are applied for the ADCP bathymetric dataset acquired from Han-Cheon in Jeju Island to validate themselves applicability.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.2
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• pp.25-35
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• 2016

Since a sophisticated location determination technology (LDT) is necessary for accurate positioning in urban area environments, numerous studies related to the LDT using the RFID (Radio Frequency IDentification) technology have been implemented for real-time positioning and data transferring. However, there are still lots of unsolved questions especially regarding what to use as base stations and what are corresponding results under the intrinsic complexity of alignment and configuration of components used for the RFID positioning. This study proposes the street light fixtures as base stations where the RFID receivers will be embedded for the mobile tracking scheme. As street light fixtures are usually installed at a certain distance interval, they can be used as base stations for the RFID receiver installation. Using the principle of the single row triangle network, the RFID receiver organization is determined based on the experiments such as recognition distance measurement and tag position accuracy estimation at inside and outside of the single row triangle network. The results verify that the mobile tracking scheme which uses RFID-embedded street light fixtures, suggested and configured in this study, is effective for the real-time outdoor positioning.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.15-25
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• 2007

This paper aims at testing the applicability of RFID (radio frequency identification) based link travel time estimation algorithm in urban street settings in Jeju island Korea. For this, we developed algorithm and compared link travel times derived from the RFID probe based algorithm with those from (already available) GPS based link travel time estimation algorithm and with the actual link travel times from survey. RFID readers are composed of master reader and slave reader and the participating passenger cars were supposed to be equipped with RFID tag inside the vehicle. The data were sent to traffic information center and we used those data in comparison. The algorithm produced link travel times in a successful manner and the accuracy of those link travel times was about 88%. For the same link segments, the accuracy of GPS based link travel times was 93%. The t-test showed that both RFID and GPS based link travel times were not different in accuracy from statistical point of view. The applicability of RFID was tested successfully and the algorithm proposed seemed to be used in similar urban settings. Some limits and future research agenda have also been presented.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.41-49
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• 2012

Radio Frequency Identification(RFID) technology, which replace BAR CODE technology that has been widely utilizing in the field of the manufacturing industry for a long time, has been proven in the whole industries including national defense, transportation, and construction as well as manufacturing industry. Recently, with this trend, researches for adapting the RFID technology have been attempting continually centering on the architectural project in the construction industry. However, those researches are mainly focusing on the experimental utilization such as simple activity and material management. To solve these issues, this study demonstrated methodologies for adapting the RFID technology by the construction steps aiming to analyze cycle time of five types of construction process to the NATM method of tunneling work. Besides, the application of RFID technology in civil engineering work was verified by demonstrating the suggested methodology to actual sites. Therefore, it is expected that the suggested methodology will be utilized for predicting the progress rate and establishing of follow-up work plans, and the site applicability of the RFID technology will be expanded to the civil engineering projects.

• Journal of Animal Science and Technology
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• v.56 no.8
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• pp.28.1-28.6
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• 2014

This study was conducted to estimate the effective population size using SNPs data of 240 Jeju horses that had raced at the Jeju racing park. Of the total 61,746 genotyped autosomal SNPs, 17,320 (28.1%) SNPs (missing genotype rate of >10%, minor allele frequency of <0.05 and Hardy-Weinberg equilibrium test P-value of < $10^{-6}$) were excluded after quality control processes. SNPs on the X and Y chromosomes and genotyped individuals with missing genotype rate over 10% were also excluded, and finally, 44,426 (71.9%) SNPs were selected and used for the analysis. The measures of the LD, square of correlation coefficient ($r^2$) between SNP pairs, were calculated for each allele and the effective population size was determined based on $r^2$ measures. The polymorphism information contents (PIC) and expected heterozygosity (HE) were 0.27 and 0.34, respectively. In LD, the most rapid decline was observed over the first 1 Mb. But $r^2$ decreased more slowly with increasing distance and was constant after 2 Mb of distance and the decline was almost linear with log-transformed distance. The average $r^2$ between adjacent SNP pairs ranged from 0.20 to 0.31 in each chromosome and whole average was 0.26, while the whole average $r^2$ between all SNP pairs was 0.02. We observed an initial pattern of decreasing $N_e$ and estimated values were closer to 41 at 1 ~ 5 generations ago. The effective population size (41 heads) estimated in this study seems to be large considering Jeju horse's population size (about 2,000 heads), but it should be interpreted with caution because of the technical limitations of the methods and sample size.