• The Journal of the Acoustical Society of Korea
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• v.32 no.2
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• pp.104-115
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• 2013

In a shallow water waveguide, reverberation signals and their Doppler effects form the primary limitation on sonar system performance. Therefore, in the reverberation-limited environment, it is necessary to estimate the reverberation level to be encountered under the conditions in which the sonar system is operated. In this paper, high-frequency reverberation model capable of simulating the reverberation signals received by a high-speed moving source in a range independent waveguide is suggested. In this model, eigenray information from the source to each boundary is calculated using the ray-based approach and the optimizing method for the launch angles. And the source receiving position changed by the moving source is found by a scattering path-finding algorithm, which considers the speed and direction of source and sound speed to find the path of source movement. The scattering effects from sea surface and bottom boundaries are considered by APL-UW scattering models. The model suggested in this paper is verified by a comparison to the measurements made in August 2010. Lastly, this model reflects well statistical properties of the reverberation signals.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.201-208
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• 2013

This paper is a study of an empirical design of an open-ended coaxial cavity resonator. It can be done by using the radius of the inner conductor, the inner radius and the length of the resonator. However, the basic coaxial transmission -line theory can be seen that the characteristics of the resonant frequency and the Q value are varied by the change of length, regardless of the value of radius of the inner conductor and inner radius of the resonator. We find out the impact of radius of the inner conductor, inner radius of the resonator and the length of the resonator parameter and propose the optimized empirical resonator design method by reducing the error between the theoretical value and the design value. Based on the simulation, several resonators are fabricated by the size of 14 mm for the radius of inner conductor, 2 mm, 5 mm, 10 mm respectively for the inner radius of resonator, and 8.5 mm for the length of the resonator. The resonant frequencies of the produced resonators were measured at 6.1, 5.7, 6.5 GHz respectively. According to the result of simulation and measurement, we know that we can design the relatively exact open-ended coaxial cavity resonator by applying the basic coaxial transmission-line theory directly when the length of the resonator is less than 10 mm, and adding the correction factor of 0.5 GHz to the calculated resonant frequency in case of more than 10 mm of the length of the resonator.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.10
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• pp.1008-1016
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• 2013

SAR measurement which was applied only to the mobile phone has been expanded in the Korean radio regulation law to the portable wireless communication equipments within 20 cm from the human body since Jan. 2012. The two-way radio operating at 150 MHz frequency band was newly included following the revised radio regulation in the target equipment of measurement. SAR measurement system at 150 MHz satisfying this regulation is necessary accordingly for SAR conformity assessment. The international SAR measurement standard(IEC 62209-2) includes the evaluation method on frequencies above 300 MHz, and the commercial SAR measurement system can measure SAR above 300 MHz only. The size of the reference dipole antenna(760 mm, return loss: -27.57 dB) and flat phantom ($1,300 mm(L){\times}900 mm(W){\times}200 mm(H)$), targeted SAR values for numerical analysis(1 g: 1.08 W/kg, 10 g: 0.77 W/kg) for SAR validation evaluation at 150 MHz frequency are proposed in this paper. The suggested dipole antenna and flat phantom are assembled and used to verify the conformity assessment of commercial SAR measurement system. The measured SAR values of 1 g and 10 g were obtained respectively to be 1.13 W/kg, 0.81 W/kg, and they satisfied the effective range(within ${\pm}10$ %) of IEC international standard. The standards based on this study are expected to be used for the domestic SAR measurement standard and IEC(International Electrotechnical Commission) international standard.

• Korean Journal of Hospice Care
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• v.5 no.1
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• pp.14-25
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• 2005

This study was conducted to examine the present state, types of services, difficulties, education programs, motivation, satisfaction and attitude of hospice volunteers and also to suggest supporting programs for the volunteer. For these purposes, a questionnaire was distributed among the 200 hospice volunteers in ten hospice organizations in Daejeon and Chungcheong province. In this research, 85.5% of the respondents were women and most of them were housewives in their forties and fifties. The majority of hospice volunteers had an education background of more than high school. Christianity (94%) was the dominant religion of volunteers. Among the service area of the hospice, emotional caring, such as listening closely and establishing empathy were the most frequently done by the respondents and the next one was spiritual care. Hospice volunteers who had started with altruistic motivation show more dynamic activities in emotional, spiritual, physical caring and so on, than those with non-altruistic motivation. Most of the respondents expressed that they felt a hospice volunteer was valuable. However they had a hard time to overcome the sorrow coming from sharing empathy with the dying patients. Those who had started with altruistic motivation usually took part in two times per a week and had more positive attitude. Volunteers who had been working more than five years showed better attitude than those who had been working less than three years. The longer the voluntary services, the more positive attitude experienced by volunteers. Hospice volunteers encountered the most considerable difficulty with lack of background knowledge and their actual capability. Insufficiency of time was the next reason for the considerable difficulty of the hospice volunteer. On the other hand, those who served more than twice per week replied that lack of background knowledge and their capability were the least considerable difficulty. Insufficiency of time was the reason of difficulty for male volunteers, as well as for females under thirty and those in their forties and fifties respectively. Generally most of the hospice volunteers (70%) were satisfied with their services and they usually satisfied with physical caring, spiritual caring, hospice's family caring. The less difficulty in voluntary services, more satisfaction for the volunteers in the end. There is a positive correlation between a attitude of the hospice volunteer and frequency of voluntary services while the volunteers' difficulty affect negatively their attitude as well as the frequency of voluntary services. Most of the hospice volunteers want to have more education about basic skills, volunteer's attitude and role, spirituality, the way of attending on the hospice and so on. Most of them considered discussion and sharing different cases as the most effective method. They also wish to had more supporting programs for the hospice volunteers(in the order of their needs) such as regular events, newsletters, personal concern, social meetings among the volunteers, insurance and minimum expenses. Based on the study results, more programs should be run in order to activate the voluntary services regardless of their gender and education background. A continuous practical supporting policy and education programs are required in order to provide special education and training courses considering every field of voluntary services. Expanding the role of the volunteers allows them more opportunities to take part in voluntary services and th activate participation. It is necessary to establish a new hospice system as a part public medical system, which can not only facilitate the voluntary services for a hospice but also enhance professional hospice volunteers. Finally, experts are needed to operate the voluntary services effectively.

• Journal of Life Science
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• v.20 no.5
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• pp.703-709
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• 2010

Glucuronidation is a major pathway for NNAL [4-(methylnitrosamno)-1-(3-pyridyl)-1-butanol] and UGT2B17 (UGT, uridine diphospho-glucuronosyltransferase) is from the UGT2B family that glucuronidates carcinogens. UGT2B17 deletion was associated with decreased levels of NNAL and with increased risk of some cancers. The UGT2B17 gene varies in copy number from zero to two per individual in humans. To examine whether UGT2B17 gene deletion is associated with the risk of lung cancer, we investigated copy number variants (CNV) in 271 cancer-free controls and 176 cases of lung cancer in Koreans by a PCR-based method. The frequency of the UGT2B17 deleted alleles was much higher than in other Caucasian and African-American groups which have already been reported. While only up to 10% of Caucasians have zero copies of the gene, up to 74% of Koreans in this study showed that both copies of the gene were deleted. Furthermore, the overall frequency of this dual deletion in female groups was higher than in male groups. However, there was no association between CNV in UGT2B17 and lung cancer. This result suggested that the UGT2B17 deletion allele was not associated with the susceptibility of lung cancers in the Korean group. However, this UGT2B17 CNV polymorphism may be a useful marker for evolutionary analysis among races.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.72-77
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• 2010

The Incheon Bridge, which was opened to the traffic in October 2009, is an 18.4 km long sea-crossing bridge connecting the Incheon International Airport with the expressway networks around the Seoul metropolitan area by way of Songdo District of Incheon City. This bridge is an integration of several special featured bridges and the major part of the bridge consists of cable-stayed spans. This marine cable-stayed bridge has a main span of 800 m wide to cross the vessel navigation channel in and out of the Incheon Port. In waterways where ship collision is anticipated, bridges shall be designed to resist ship impact forces, and/or, adequately protected by ship impact protection (SIP) systems. For the Incheon Bridge, large diameter circular dolphins as SIP were made at 44 locations of the both side of the main span around the piers of the cable-stayed bridge span. This world's largest dolphin-type SIP system protects the bridge against the collision with 100,000 DWT tanker navigating the channel with speed of 10 knots. Diameter of the dolphin is up to 25 m. Vessel collision risk was assessed by probability based analysis with AASHTO Method-II. The annual frequency of bridge collapse through the risk analysis for 71,370 cases of the impact scenario was less than $0.5{\times}10^{-4}$ and satisfies design requirements. The dolphin is the circular sheet pile structure filled with crushed rock and closed at the top with a robust concrete cap. The structural design was performed with numerical analyses of which constitutional model was verified by the physical model experiment using the geo-centrifugal testing equipment. 3D non-linear finite element models were used to analyze the structural response and energy-dissipating capability of dolphins which were deeply embedded in the seabed. The dolphin structure secures external stability and internal stability for ordinary loads such as wave and current pressure. Considering failure mechanism, stability assessment was performed for the strength limit state and service limit state of the dolphins. The friction angle of the crushed stone as a filling material was reduced to $38^{\circ}$ considering the possibility of contracting behavior as the impact.

• 대한공업교육학회지
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• v.41 no.1
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• pp.1-21
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• 2016

The purpose of this study is to analyze job of die and mold makers for apprenticeship education of specialized high school using DACUM method. The contents of this study were to identify the duties, specific tasks performed and the level of importance, difficulty, frequency and entry level on each task. This study also make out a DACUM chart of die and mold makers for apprenticeship education of specialized high school. The DACUM committee, which consisted of one facilitator, nine die and mold experts, one recorder and one coordinator, was established to conduct DACUM. The conclusions are as follows; First, this study defines a die and mold makers as 'a person who make it possible to manufacture/assemble/inspect die and mold parts using various machine tool'. Second, duties in job of die and mold makers for apprenticeship education were total 12 and total tasks in job of die and mold makers for apprenticeship education were 86. Third, this study determine the level of importance, difficulty, frequency and entry level about each task. Finally, this study make out a DACUM chart of die and mold makers for apprenticeship education of specialized high school based on the results of DACUM job analysis. And knowledge, skills, tools, and positive behaviors, future trends/concerns about die and mold makers for apprenticeship education of specialized high school were presented.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.4
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• pp.354-361
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• 2004

This Paper describes a crack scattering model for SH wave based on the boundary integral equation(BIE) method, where the fundamental unknown is crack opening displacement(COD). When a time harmonic plane wave was incident on a 2-D isolated crack (slit) of width 2a, the COD distributions were numerically calculated as a function of ka. The calculated COD agreed well with results obtained with other methods. The far-field scattering amplitude, which completely characterizes the flaw response, was calculated in two ways. The Kirchhoff approximation and the BIE-COD exact formulation were compared in terms of incidence angle and frequency ka in a pulse-echo mode. Maximum response was obtained for both methods at the specular reflection direction. Away from the specular direction, the Kirchhoff approximation becomes less accurate. The time domain crack response was also calculated using a band-limited spectrum of center frequency 10 MHz. At oblique incidence to the crack both methods show the existence of an antisymmetric flash points occurring from the crack edge. The Kirchhoff approximation provides an exact time interval between flash points, although it unrealistically gives the same amplitude.

• Journal of Nutrition and Health
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• v.47 no.3
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• pp.193-205
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• 2014

Purpose: This study was conducted in order to investigate nutrient and food intake status and dietary quality in Korean adults according to nutrition label utilization. Methods: We analyzed data from the combined 2010-2011 KNHANES (Korean National Health and Nutrition Examination Survey). The analysis included 8190 adults aged 19 to 64 years. In this study, according to nutrition label utilization, we classified the subjects according to the "non-utilization of nutrition label (NUNL)" group (male, n = 2716, female, n = 3147), "identification of nutrition label (INL)" group (male, n = 143, female, n = 330), and "Utilization of nutrition label (UNL)" group (male, n = 363, female, n = 1491). Nutrient and food group intake, NAR (nutrient adequacy ratio), MAR (mean adequacy ratio), and INQ (index of nutritional quality) were analyzed using data from the 24-recall method. Results: Results of this study showed that subjects in the NUNL group were significantly more likely to drink alcohol compared with the other two groups. The NUNL group showed a significantly higher frequency of consuming instant noodles, Soju (male), and carbonated drink (female) than the UNL group, whereas the NUNL group showed a significantly lower frequency of consuming milk, soymilk, and yogurt than the UNL group. In addition, regarding diet quality (NAR and INQ), significantly lower vitamin $B_2$, vitamin C, and calcium was observed in the NUNL group compared with the UNL group. For both male and female, significantly higher MAR was observed in the UNL group than in the NUNL group. The NUNL group showed significantly lower consumption of milk compared to the UNL group. Conclusion: Good dietary practice such as referring to nutrition labels and its influence can affect the quality of nutritional intake and selection of food, while it can also provide basic data for specific nutrition education regarding use of nutrition labeling.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.221-227
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• 2021

In this paper, we conducted word-to-word similarity analysis of standardized datasets collected through web crawling for 10,000 Vertical Noise Mouses using Word2Vec, and made 92 students of computer engineering use the products presented for 5 days, and conducted self-report questionnaire analysis. The questionnaire analysis was conducted by collecting the words in the form of a narrative form and presenting and selecting the top 50 words extracted from the word frequency analysis and the word similarity analysis. As a result of analyzing the similarity of e-commerce user's product review, pain (.985) and design (.963) were analyzed as the advantages of click keywords, and the disadvantages were vertical (.985) and adaptation (.948). In the descriptive frequency analysis, the most frequently selected items were Vertical (123) and Pain (118). Vertical (83) and Pain (75) were selected for the advantages of selecting the long/demerit similar words, and adaptation (89) and buttons (72) were selected for the disadvantages. Therefore, it is expected that decision makers and product planners of medium and small enterprises can be used as important data for decision making when the method applied in this study is reflected as a new product development process and a review strategy of existing products.