• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.4
• /
• pp.84-91
• /
• 2011

Recently, WBAN(Wireless Body Area Network) which has progressed standardization based on IEEE 802.15.6 standardization is a network for the purpose of the short-range wireless communications within around 3 meters from the inner or outer human body. Effective QoS control technique and data efficient management in limited bandwidth such as audio and video are important elements in terms of users and loads in short-range wireless networks. In this paper, for high-speed WBAN IEEE 802.15.6 standard, the dynamic allocation to give an efficient bandwidth management and weighted fair queueing algorithm have been proposed through the adjustment of the super-frame about limited data and Quality of Service (QoS) based on the queuing algorithm. Weighted Fair Queueing(WFQ) Algorithm represents the robust performance about elements to qualitative aspects as well as maintaining fairness and maximization of system performance. The performance results show that the dynamic allocation expanded transmission bandwidth five times and the weighted fair queueing increased maximum 24.3 % throughput and also resolved delay bound problem.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.2
• /
• pp.118-124
• /
• 2008

For forward error correction, DVB-S2, which is the digital video broadcasting forward error coding and modulation standard for satellite television, uses a system based the concatenation of BCH with LDPC inner coding. In DVB-S2 the LDPC codes are defined for 11 different code rates, which means that a DVB-S2 LDPC decoder should support multiple code rates. Seven of the 11 code rates, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9, and 9/10, are regular and the rest four code rates, 1/4, 1/3, 2/5, and 1/2, are irregular. In this paper we propose a flexible decoder for the regular LDPC codes. We combined the partially parallel decoding architecture that has the advantages in the chip size, the memory efficiency, and the processing rate with Benes network to implement a DVB-S2 LDPC decoder that can support multiple code rates with a block size of 64,800 and can configure the interconnection between the variable nodes and the check nodes according to the parity-check matrix. The proposed decoder runs correctly at the frequency of 200MHz enabling 193.2Mbps decoding throughput. The area of the proposed decoder is $16.261m^2$ and the power dissipation is 198mW at a power supply voltage of 1.5V.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.167-174
• /
• 2001

Reflection method using ultrasonic source has been attempted to obtain the information about tunnel lining structures composed of lining, shotcrete, water barrier and voids at the back of lining. In this work, two different types of sources, i.e. single-pulse source and sweep source, can be used. Single-pulse source with short time duration has the frequency content whose amplitudes tend to be concentrated around the dominant frequency, whereas sweep source with long time duration denotes a flat distribution of relatively larger amplitude over a broad frequency band, although the peak to peak amplitude of single-pulse source wavelet is equivalent to that of sweep source one. In traditional seismic application, a single-pulse source(weight drop, dynamite) is typically used. However, to investigate the fine structure, as it is the case in the tunnel lining structure, the sweep wavelet can be also a desirable source waveform primarily due to the higher energy over a broad frequency band. For the investigation purposes of sweep source, a physical modeling is a useful tool, especially to study problems of wave propagation in the fine layered media. The main purpose of this work was using a physical modeling technique to explore the applicability of sweep source to the delineation of inner layer boundaries. To this end, a two-dimensional physical model analogous to the lining structure was built and a special ultrasonic sweep source was devised. The measurements were carried out in the sweep frequency range 10 ∼ 60 KHz, as peformed in the regular reflection survey(e.g. roll-along technique). The measured data were further rearranged with a proper software (cross-correlation). The resulting seismograms(raw data) showed quitely similar features to those from a single-pulse source, in which high frequency content of reflection events could be considerably emphasized, as expected. The data were further processed by using a regular data processing system "FOCUS" and the results(stack section) were well associated with the known model structure. In this context, it is worthy to note that in view of measuring condition the sweep source would be applied to benefit the penetration of high frequency energy into the media and to enhance the resolution of reflection events.

• Child Health Nursing Research
• /
• v.7 no.4
• /
• pp.421-433
• /
• 2001

The purpose of this phenomenological study was to understand the lived experience of mothers of children with muscular dystrophy. The participants were 11 mothers recruited by snowball sampling, who agreed with the objectives of the research and could verbally communicate with the researcher and who lived with their sons who had muscular dystrophy. Data collection was done through in-depth interviews with participants in their own homes. Each interview took 50 to 120 minutes. All of the interviews were audiotaped and then transcribed. Data were analyzed using Colaizzi's (1978) method of phenomenology. From the transcripts 109 significant sentences and phrases were selected and 13 clusters of themes were categorized from 67 significant statements. These results were integrated into the essential structure of the lived experience of mothers of children with muscular dystrophy. 1. Anxious and relying on chance due to indefinite diagnosis. 2. Only able to cry with shock because of son's fatal disease. 3. Seeing the future as dismal and feeling resentment that this disease in transmitted through the mother. 4. Feeling caught between a husband who is distancing himself from his family and the family which is disintegrating. 5. Feeling like a sinner for transmission of genetic disease(Feeling guilt for conceiving a son with a genetically transmitted fatal disease). 6. Empathizing with other suffers of muscular dystropy and their parents in their grief and helping to dissipate their heavy feelings. 7. Deciding to sacrifice self as a way of taking responsibility for giving birth to a handi-capped son. 8. Losing hope (feeling despair) as son's condition deteriorates in spite of all attempts to help him. 9. Wishing to die with son who becomes progressively immobile. 10. Accumulating Han*(한, 恨), because of rising Hwa(화, anger), and becoming sick both mentally and physically. 11. Seeing events as destiny and finding self-control through faith. 12. Finally, giving up sacrificing self for son and becoming concerned(involved) with other children in the family. 13. Feeling fear at son's impending death. This is the first research on the experience of Korean mothers of children with muscular dystrophy. In applying the phenomenology research method, this study not only helps health professionals understand the experience of these mothers in the Korean patriarchal social system, but the researcher, as a nurse, can share their agony and grief through identification of their inner world through in-depth personal interviews. The results obtained in this study will not only help in the development of family nursing practice for families with genetically transmitted diseases but also prepare basic data for family nursing practice in the Korean sociocultural context.

• Progress in Medical Physics
• /
• v.29 no.2
• /
• pp.47-52
• /
• 2018

To investigate the effect of low magnetic field on dose distribution in SABR plans for liver cancer, we calculated and evaluated the dose distribution to each organ with and without magnetic fields. Ten patients received a 50 Gy dose in five fractions using the $ViewRay^{(R)}$ treatment planning system. For planning target volume (PTV), the results were analyzed in the point minimum ($D_{min}$), maximum ($D_{max}$), mean dose ($D_{mean}$) and volume receiving at least 90% ($V_{90%}$), 95% ($V_{95%}$), and 100% ($V_{100%}$) of the prescription dose, respectively. For organs at risk (OARs), the duodenum and stomach were analyzed with $D_{0.5cc}$ and $D_{2cc}$, and the remained liver except for PTV was analyzed with $D_{mean}$, $D_{max}$, and $D_{min}$. Both inner and outer shells were analyzed with the point $D_{min}$, $D_{max}$, and $D_{mean}$, respectively. For PTV, the maximum change in volume due to the presence or absence of the low magnetic field showed a percentage difference of up to $0.67{\pm}0.60%$. In OAR analysis, there is no significant difference for the magnetic field. In both shell structure analyses, although there are no major changes in dose distribution, the largest value of deviation for $D_{max}$ in the outer shell is $2.12{\pm}2.67Gy$. The effect of low magnetic field on dose distribution by a Co-60 beam was not significantly observed within the body, but the dose deposition was only appreciable outside the body.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.10
• /
• pp.696-706
• /
• 2017

The purpose of this study was to verify experimentally debris reduction facilities for culverts installed in small rivers. A culvert is defined as a structure laid under a road or a railroad that passes through an inner urban area or downtown area to make an artificial canal. Culverts are generally categorized into road culverts or waterway culverts, among which the latter are artificial structures designed to discharge running water into a river. At the time of floods, the structural safety of waterway culverts can be undermined by the accumulation of debris, such as soil, boughs and weeds, and they may be at risk of overflowing due to blockages. Debris reduction facilities are necessary to prevent such damage. In this study, the effects of the three existing types of debris reduction facilities were examined through hydraulic experiments. The results of the experiments showed that vertical separation to divert debris reduced the accumulation rate by 27.65 to 31.39 percent. The two types of screen designed to block and divert debris, respectively, were found to have excellent debris blocking abilities. However, when the effects of the rising water level are considered simultaneously, the screen to divert debris was found to show superior effects. The screen to block debris can be considered to have excellent debris blocking ability, but requires the continuous collection of the debris, due to the high risk of rising water levels caused by its accumulation.

• Journal of Navigation and Port Research
• /
• v.31 no.5 s.121
• /
• pp.435-445
• /
• 2007

Ship structures are thin-walled structures and lots of cutouts, for example, of inner bottom structure, girder, upper deck hatch, floor and dia-frame etc. In the case where a plate has cutout it experiences reduced buckling and ultimate strength and at the same time the in-plane stress under compressive load produced by hull girder bending will be redistributed. In the present paper, we investigated several kinds of perforated stiffened model from actual ship structure and series of elasto-plastic large deflection analyses were performed to investigate into the influence of perforation on the buckling and ultimate strength of the perforated stiffened plate varying the cutout ratio, web height, thickness and type of cross-section by commercial FEA program(ANSYS). Closed-form formulas for predicting the ultimate strength of the perforated stiffened plate are empirically derived by curve fitting based on the Finite Element Analysis results. These formulas are used to evaluate the ultimate strength, which showed good correlation with FEM results. These results will be useful for evaluating the ultimate strength of the perforated stiffened plate in the preliminary design.

• Progress in Medical Physics
• /
• v.13 no.2
• /
• pp.85-89
• /
• 2002

We authors developed a new small-size birdcage RF coil for animal MR images. And we compared signal-to-noise ratio (SNR) of the new small coil with a conventional knee coil. The dimension of the low-pass type birdcage coil with 12 elements at 37 MRI system are 13 cm outer diameter, 12 cm inner diameter and 20 cm length. For each element, the width of copper tape is 0.05 mm, thickness is 8 mm and length is 20 cm. The small birdcage coil with 12 elements exhibited 7 resonance modes. The isolation of the quadrature channel could be achieved more than 20 ㏈. The coil quality factor (Q value) was 98.6. The SNR of the animal coil was 243.2 on the average and was about twice as high as the conventional knee coil. The present study successfully demonstrated that the small birdcage coil could provide high quality animal MR images with the improved SNR. Therefore, it is expected that the small birdcage coil could be used in the clinical diagnosis and research studies for veterinary medicine in the near future.

• Korean Journal of Oriental Medicine
• /
• v.13 no.3
• /
• pp.119-124
• /
• 2007

Introduction: In Oriental medicine, the status of tongue is the important indicator to diagnose one's health, because it represents physiological and clinicopathological changes of inner parts of the body. The method of tongue diagnosis is not only convenient but also non-invasive, so tongue diagnosis is most widely used in Oriental medicine. By the way, since tongue diagnosis is affected by examination circumstances a lot, its performance depends on a light source, degrees of an angle, a medical doctor's condition etc. Therefore, it is not easy to make an objective and standardized tongue diagnosis. In order to solve this problem, in this study, we tried to design a discriminant function for thick and thin coating with color vectors of preprocessed image. Method: 52 subjects, who were diagnosed as white-coated tongue, were involved. Among them, 45 subjects diagnosed as thin coating and 7 subjects diagnosed as thick coating by oriental medical doctors, and then their tongue images were obtained from a digital tongue diagnosis system. Using those acquired tongue images, we implemented two steps: Preprocessing and image analyzing. The preprocessing part of this method includes histogram equalization and histogram stretching at each color component, especially, intensity and saturation. It makes the difference between tongue substance and tongue coating was more visible, so that we can separate tongue coating easily. Next part, we analyzed the characteristic of color values and found the threshold to divide tongue area into coating area. Then, from tongue coating image, it is possible to extract the variables that were important to classify thick and thin coating. Result : By statistical analysis, two significant vectors, associated with G, were found, which were able to describe the difference between thick and thin coating very well. Using these two variables, we designed the discriminant function for coating classification and examined its performance. As a result, the overall accuracy of thick and thin coating classification was 92.3%. Discussion : From the result, we can expect that the discriminant function is applicable to other coatings in a similar way. Also, it can be used to make an objective and standardized diagnosis.

• The Journal of Industrial Distribution & Business
• /
• v.8 no.5
• /
• pp.95-109
• /
• 2017

Purpose - The purpose of this study is to classify the quality factors of coffee shop customers with the service quality based on the SERVQUAL, selection attributes, and service qualities used in previous studies. The path structure of coffee shops' quality factors → customer satisfaction → trust → behavioral intention was analyzed in order to confirm the system of coffee shops' quality factors. Research design, data, and methodology - The survey of was conducted with college students of Kangwon University. A total of 250 questionnaires were distributed, with 232 collected. Of them, Excluding 36 respondents' because of incomplete answers and missing values, 196 responses were used in the final analysis. Empirical analysis was made through factor analysis, correlation analysis, multiple regression analysis, simple regression analysis and mediating regression analysis by using Statistics Package SPSS 19.0. Results - The results are as follows: Firstly, coffee shops' quality factors were classified into seven categories like service encounter quality, product quality, cleanliness, overall interior, purchase quality, convenience, and aesthetics. Secondly, service encounter quality, product quality, purchase quality, and aesthetics had a positive effect on customer satisfaction, respectively. Thirdly, it showed that service encounter quality, product quality, overall interior, purchase quality, and aesthetics had a positive effect on trust, respectively. Fourthly, customer satisfaction had a positive effect on behavioral intention. Lastly, after verifying the effect relations of trust between customer satisfaction about coffee shop and behavioral intention, customer satisfaction has a positive effect on trust and trust has a positive effect on behavioral intention. On the other hand, trust did not have a mediating effect between customer satisfaction and behavioral intention. But, cleanliness, convenience, and overall interior did not have a positive effect on customer satisfaction. Conclusions - Coffee shop consumers put importance on price, discount systems, taste, and freshness, but more on courteous and kind services of coffee shop staff or comfortable and calming atmosphere of inner space. Thereby, coffee shop marketers need to take factors like service encounter quality and aesthetics into more consideration. In addition, customer satisfaction has an effect on trust, while trust on behavioral intention, even though trust is not mediated between customer satisfaction and behavior intention.