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        검색결과 638

        122.
        2017.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigate the radio properties of the dwarf galaxy SDSS J133245.62+263449.3 which shows optical signatures of black hole activity. Dwarf galaxies are known to host intermediate mass black holes (IMBHs) with masses MBH ∼ 10 4-6 M⊙, some of them being radio loud. Recently, Reines et al. (2013) found dwarf galaxy candidates which show signatures of being black hole hosts based on optical spectral lines. SDSS J133245.62+263449.3 is one of them; it shows a flux density of ∼ 20 mJy at 1.4 GHz, which corresponds to L 1.4GHz ∼ 10 23 WHz -1. This is much brighter than other black hole host dwarf galaxies. However, star formation activity can contribute to radio continuum emission as well. To understand the nature of the radio emission from SDSS J133245.62 + 263449.3, we imaged this radio loud dwarf galaxy at low frequencies (325 MHz and 610 MHz) using the Giant Metrewave Radio Telescope (GMRT). We present here the high resolution images from our GMRT observations. While we detect no obvious extended emission from radio jets from the central AGN, we do find the emission to be moderately extended and unlikely to be dominated by disk star formation. VLBI observations using the Korean VLBI Network (KVN) are now being planned to understand the emission morphology and radiation mechanism.
        4,000원
        126.
        2017.10 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구에서는 표전 근전도 신호를 기반으로 기존의 재활로봇 알고리즘의 성능의 개선하기 위한 새로운 특징 요소를 개발 및 검증하였다. 연구방법 : 기존의 선형 재귀 모델을 기반으로 한 실시간 로봇 제어 알고리즘을 수정하여, 2개 이상의 주파수 특징을 가지는 근 전도신호에 그 특징의 수에 맞추어 주파수 영역을 다르게 한 모델을 개발하였다. 결과 : 측정된 결과 개선된 알고리즘의 모델이 기존 모델대비 높은 정확도가 나옮을 확인할 수 있었으며, 향후 이를 적용 한다면, 근전도 기반 재활로봇의 정확도가 향상될 수 있음을 확인할 수 있었다. 결론 : 본 연구에서 제안된 복수의 필터뱅크 특징을 기반으로 한 개선될 선형 재귀알고리즘이 기존 알고리즘보다 높은 성능을 보임을 확인할 수 있었다. 이를 바탕으로 향후 뇌졸중 환자의 치료를 위한 재활 로봇을 제어하는데 활용된다면, 환자의 의지를 더욱 정확히 반영한 재활치료를 통하여 환자의 재활치료효과를 증진시킬 것이라 기대된다.
        4,000원
        127.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is a study on the cracking of the main piston surface which is generated in the injection molding machine to generate mold force. The main piston machining process consists of high frequency heat treatment, grinding and super finishing after lathe turning. Scale, defect size, and fracture texture were observed for four cracks on the surface of the piston during the tempering process after high frequency heat treatment using a metallurgical microscope. In this study, it was confirmed that the cracked structure of the piston structure was ferrite and pearlite structure. It was confirmed that cracks progressed to 480 ㎛ and scale layer of 3 ㎛ or less. Surface hardening layer and hardness were min 2.0mm/HRc 58±2 spec 1.6 mm/HRc 56.5~57.5 In addition, cracks on the surface of the piston appear perpendicular to the rolling process. Therefore, it can be assumed that the crack occurred in the low temperature tempering process at 200°C or less after the high frequency heat treatment, not the material defect. Therefore, the temperature should be maintained at 200°C or higher during tempering after high-frequency heat treatment, and the cracking defect on the surface of the piston can be prevented by setting the feed rate to 1.3 mm/s or less during heat treatment.
        4,000원
        128.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the nutrition knowledge, dietary habits, and food intake frequency according to hospitalization after breast cancer surgery and experience of breast cancer among female adults residing in the Bucheon area. Subjects were 52 female breast cancer survivors 27 in the hospitalization group (HG) and 25 in the non-hospitalization group (non-HG)] and 52 controls. Data included the results of self-administered questionnaires, as well as anthropometric data and blood biochemical values of breast cancer survivors collected from electronic medical records. Statistical analysis was performed using SPSS 20.0 program. Nutrition knowledge and dietary habits revealed no significant differences between HG and non-HG, but intake frequency of root and tuber crops and kimchi was significantly higher in the HG group than the non-HG group (p<0.05). According to experience of breast cancer, total scores of nutrition knowledge among survivors (8.2) were significantly higher than those of the control group (6.3) (p<0.001). Fish and shellfish and fruit intake frequencies were significantly higher in the survivors group, whereas intake frequency of fast food, convenience food, and alcohol was significantly lower compared to the control group. Overall, these findings indicate it is necessary to develop and spread nutrition education guidelines to prevent the occurrence and recurrence of breast cancer.
        4,000원
        129.
        2017.10 구독 인증기관·개인회원 무료
        The Azuki bean weevil, Callosobruchus chinensis L., is a common insect pest of stored products in the world. Radio-frequencydependent oviposition, development and adult performances of C. chinensis were examined at five radio-frequencies of0 (control), 5, 10, 20, and 30 kHz on azuki bean, cowpea, and mung bean seeds. The effects were studied on two successivegenerations of C. chinensis. The results showed that radio-frequency application have significant effects on the life variablesof C. chinensis. Radio-frequency exposures on three seed species not only impacted on developmental time, adult longevityand adult weight but negative effects were also transmitted to the successive generations. Longer developmental time andthe least adults of C. chinensis were emerged with shorter longevity in case of radio-frequency treatment than untreated.Decreasing the radio-frequency level further reduced the adult longevity and increased time for development of adults.The least adult emergence and short longevity was recorded for 5 kHz treatment. Radio-frequency treatments have alsoaffected on the adult performance such as weight of adult. The life variables of C. chinensis are discussed in terms oftargeting susceptibilities to radio-frequencies in storage as an alternative to chemical treatments.
        130.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 농구 경기장내 마케팅의 효용성을 확인하기 위해서 마케팅의 여러 연구 기법들 중 시선추적 기술을 이용하여 동공이 확장 되었을 때의 시선 관찰 및 관심도를 측정하고 비교 분석하였다. 특히 동공이 확장된 구간을 산출하기 위해 유효테이터를 중심으로 동공의 크기가 2시그마 범위 상위 2.275%일 때의 구간별 데이터를 정리하고 이전 연구에서 산출된 3시그마의 상위 0.135%일 때의 구간별 데이터와 전체 유효 데이터를 주시 빈도에 따른 변곡점으로 구분하여 분석하였다. 또한 전체 유효 데이터와 동공의 크기가 유의미하게 커졌다고 판단되는 범위들 간의 상관도를 분석하였다. 그 결과 가장 시선이 많이 머무른 구간과 동공이 크기가 유의미하게 커진 부분은 완전히 일치하지는 않았으나, 전체 유효 데이터와 동공크기 2시그마 상위 데이터의 상관분석은 .805로 가장 높은 상관관계를 나타내었으며, 동공크기 2시그마 상위 데이터와 동공크기 3시그마 상위 데이터의 상관분석은 .781의 상관관계를 보였고 전체 유효데이터와 동공크기 3시그마 상위 데이터 상관분석은 .683의 상관관계를 보였다. 따라서 동공의 크기가 확장 되어진 구간과 시선추적 데이터에서 시선이 많이 머무른 구간이 유사함을 알 수 있었으나, 동공의 크기가 유의미하게 확장되었다고 판단되어지는 구간의 데이터 일수록 전체 데이터와의 상관도가 떨어지는 것을 알 수 있었다.
        4,000원
        131.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we have analyzed the 2015 KNHANES to understand the nutritional and health status of Korean middle-age adults from the perspective of frequency of eating breakfast. Those that eat breakfast five to seven times a week were 76.3 percent (male) and 72.7 percent (female). Frequency of eating lunch and dinner, and eating out was significantly higher among male subjects. The higher the frequency of eating breakfast, the higher the frequency of eating lunch, dinner and eating out. Female subjects that ate breakfast five to seven times a week had lower height and weight compared with other groups, but there was no significant difference of BMI and waist circumference among the four groups. Adults that eat breakfast five to seven times a week had consumed more carbohydrates, dietary fiber, phosphorus, potassium and vitamin C regardless of gender, which validates the nutritional benefits of eating meals regularly. Male adults that ate breakfast five to seven times a week revealed lower levels of diastolic blood pressure and LDL-cholesterol compared with other groups, which validates eating breakfast regularly was beneficial to their health. In conclusion, it is necessary to eat regular meals daily relative to the nutritional status and health of Korean middle-age adults.
        4,000원
        132.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 상추((Lactuca sativar L.)의 3가지 품종에 대해서 RGB LEDs의 각각의 다른 비율과, 듀티비 50% 조건의 RB LEDs를 이용한 여러 가지 주파수를 가지는 펄스광 조사가 상추의 생장과 형태형성에 미치는 영향을 살펴보기 위하여 수행되었다. 파종 후 육묘 기간을 거쳐 유사한 외형을 갖는 묘를 선발하여 재배룸의 온도와 습도, 23±1oC/50-60%(주간)과 18±1oC/70-85%(야간) 조건에서 담액수경재배로 4주간 재배하였다. 광합성유효광 량자속밀도(PPFD)는 재배베드 위에서 110±3μmol·m-2·s-1, RGB 비율은 6:3:1, 5:2.5:2.5, 3:3:4, 2:2:6, 1:1:8 이었다. 50% 듀티비를 갖는 펄스광은 RB LEDs로 구성되었고 설정된 주파수는 50, 100, 500, 1,000, 5,000, 10,000, 25,000Hz(20, 10, 0.1, 0.04ms) 이었다. RGB 비율 6:3:1 에서 적축면 상추의 생체중은 다른 RGB 처리구와 비교 하여 유의적으로 높은 값을 보였으나, 대조구인 형광등 처리구와는 유의적 차이가 발생되지 않았다. RGB 비율 1:1:8의 조건에서, 롤로로사는 생체중, 그랜드 래피드는 엽수와 생체중이 다른 RGB 처리구와 비교하여 유의적으로 낮았다. 청색광의 비율이 증가할수록, 3개 품종 모 두에서 엽장이 감소하면서 엽형이 둥근 형태로 발달하였다. RB LED로 구성된 LED 광조건 하에서 50% 듀티비 조건과 처리된 여러 주파수의 증가 또는 감소에 따른 상추의 생육 및 형태형성에 미치는 경향성을 발견하기 힘들었다.
        4,000원
        133.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background:Active trigger points (TrPs) of the suboccipital muscles greatly contribute to the occurrence of chronic tension-type headache, with increased sensitivity of TrPs and facilitated referred pain.Objects:This study aimed to investigate whether the integration of high-frequency diathermy into suboccipital release is more beneficial than the use of suboccipital release alone.Methods:Thirty subjects were assigned to either experimental group-1 (EG-1) to undergo suboccipital release combined with high-frequency diathermy (frequency: 0.3 MHz, and electrode type: resistive electronic transfer), or EG-2 to undergo suboccipital release alone, or the control group (CG) with no intervention, with 10 subjects in each group. The assessment tools included the headache impact test 6 (HIT-6), perceived level of tenderness, neck disability index, and neck mobility. Intervention was performed for 10 minutes, twice per week, for 4 weeks, and measurements were performed before and after the interventions.Results:The between-group comparison of the post-test values and changes between pretest and post-test showed significant differences for all parameters at p<.05, except for the left-to-right lateral bending range. In the post hoc test, EG-1 showed significant differences for the parameters in comparison with the CG, while no significant differences in the perceived tenderness level, on both temporal regions, were found between EG-2 and CG. Furthermore, the HIT-6 score and perceived tenderness level, in the right temporal region, showed significant differences between EG-1 and EG-2. In the within-group comparison, EG-1 and EG-2 appeared to be significantly different between pretest and post-test (p<.05), except for the perceived tenderness level in the right temporal region, with significance for the EG-1 group only (p<.05).Conclusion:These findings suggest that the suboccipital release technique may be advantageous to improve headache, tenderness, and neck function and mobility, with more favorable effects with the incorporation of high-frequency diathermy.
        4,200원
        135.
        2017.04 구독 인증기관·개인회원 무료
        In this paper, the method of vibration analysis for calculating the natural frequency is presented. This method is a simple but exact method of calculating natural frequencies corresponding to the modes of vibration for the cantilevered composite materials conical beam. The influence of natural frequency of the cantilevered composite materials conical beam is presented. This method may be extended to stability analysis of complex structureal elements.
        136.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to evaluate the risk of overweight and obesity in adolescents consuming snacks frequently from 2007~2009, Korean National Health and Nutrition Examination Survey (KNHANES). The subjects (12~14 years: n=523; 15~18 years: n=614) were presented with food frequency questionnaires, and they were classified according to their gender and frequency of snack consumption. In the age group of 12~14 years, boys and girls (boys OR: 1.11, 95% CI: 0.52~2.39, girls OR: 12.45, 95% CI: 2.26~68.51) who consumed yogurt frequently had a higher risk of overweight and obesity at the highest quartile frequency compared with the lowest quartile after adjustments for multiple confounding factors, including age, physical activity, frequency of eating out and snack consumption, and energy intake. In the age group of 15~18 years, girls (OR: 1.01, 95% CI: 0.34~2.99) consuming fried foods had a higher risk of overweight and obesity at the highest quartile frequency compared with the lowest quartile after adjustments for multiple confounding factors, including age, physical activity, frequency of eating out and snack consumption, and energy intake. Thus, we conclude that frequent consumption of yogurt and fried foods increases the risk of overweight and obesity in adolescents. These findings suggest that the risk of overweight and obesity is associated with the frequency of snack consumption.
        4,000원
        137.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the correlation between frequency of high-caffeine energy drink intake in adolescents and their mental health status using data from the Korean adolescent health behaviors online survey (2014-15). Mental health was classified by the five categories: Perception of stress (PS), Insufficient relief of fatigue after sleep (IRFS), Experience of sadness despair (SD), Suicidal ideation (SI), and Subjective unhappiness (SU). Regarding general characteristics, higher age, height, and body weight of subjects were associated with higher frequency of high-caffeine energy drink (HCED) intake (p< .0001). In the OR analysis, when the lowest group (≤2/wk) and highest group (1≥day) were compared, the highest group showed significantly higher OR in all five categories of mental health. According to gender, males did not show better PS, SD, and SI than females who had a high frequency of HCED (p for trend<.0001). According to school level, middle school students showed a higher risk rate than high school students in PS, IRFS, and SD (p for trend< .0001). Based on the above results, higher frequency of HCED intake among adolescents was associated with more adverse effects on mental health.
        4,000원
        138.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of 27.12 MHz radio frequency (RF) heating on heat transfer phenomena during the thawing process of frozen food. To determine the velocity of the RF thawing machine, samples were frozen at -80oC and subjected to different power treatments. The phase change times (-5 to 0oC) of frozen radish were 30, 26, 13, and 8 min; those of pork sirloin were 38, 25, 11, and 5 min; those of rump were 23, 17, 11, and 6 min; those of chicken breast were 42, 29, 13, and 9 min; and those of tuna were 25, 23, 10, and 5 min at 50, 100, 200, and 400 W, respectively. The heating limit temperatures of the radish, pork sirloin, rump, chicken breast, and tuna samples were 19.5, 9.2, 21.8, 8.8, and 16.8oC at 50 W; 23.5, 15.5, 27.3, 12.3, and 19oC at 100 W; 42, 26.9, 45.7, 22.1, and 39.4oC at 200 W; and 48.5, 54.7, 63.6, 57.3, and 44.9oC at 400 W. These results suggest that high-power RF improves thawing velocity and heating limit temperatures, and that an improvement on the operation of the RF thawing machine, according to food temperatures, is needed.
        4,000원
        139.
        2016.12 KCI 등재 구독 인증기관·개인회원 무료
        목 적 : DWI(Diffusion-weighted image) 검사 시 frequency방향의 FOV(field-of-view) 변화에 따른 ADC(Apparent Diffusion Coefficient) 값의 변화 여부에 대하여 알아보고자 한다. 대상 및 방법 : Single-shot EPI sequence를 이용하여 brain DWI를 진행한 6명의 환자를 대상으로 Philips medical system의 Ingenia CX 3.0T, 신호수집 코일은 32channel head coil을 사용하였다. FOV의 변화는 phase 방향을 250mm으로 고정하고, frequency 방향을 200mm~300mm까지 각각 10mm씩 변화를 주었으며, voxel size(2mm×2mm)는 동일하게 유지하였다. scan parameter는 matrix 256×256, slice thickness 4mm, gap 2mm로 총 20개의 단면 영상을 획득하였다. image J를 이용하여 뇌척수액, 백질, 회백질의 ADC 값을 측정하고, 일원배치 분산분석을 통한 사후 분석을 시행하였다. 결 과 : ADC값은 200mm에서부터 300mm로 FOV가 변화함에 따라 뇌척수액은 ±121.92mm²/s의 편차(mean: 1662.80 min: 1643.07, max: 1700.54)를 보였고, 백질은 ±39.19mm²/s(mean: 405.88min: 399.58, max: 480.23), 회백질은 ±22.91mm²/s(mean: 413.18, min: 409.61, max: 419.27)의 편차를 보였다. 일원배치 분산분석 결과, 뇌척수액, 백질, 회백질의 ADC 값 모두 통계적으로 유의한 차이를 보이지 않았으며(p>0.05), Duncan의 사후분석결과 유의수준 0.05에 대한 부집단이 모두 1개 밖에 존재하지 않아 FOV 변화에 따른 ADC 값의 차이가 없음을 알 수 있다. 결 론 : 영상 분석 시 고식적 영상, 관류 영상과 함께 DWI를 결합 시켜 병변 진단의 정확한 정보를 제공할 수 있으나 서로 다른 FOV를 사용함에 있어, 진단 분야 뿐만 아니라 연구 분야에서의 영상 분석 시 데이터, 또는 영상의 왜곡을 가져올 수 있다. 그러나 본 연구를 통해 brain 검사 시 frequency 방향으로 FOV가 변화함에 따라 ADC의 값의 변화가 없음을 알 수 있었다. 이를 토대로 다양한 인체 부위의 적정 FOV를 선택함으로써 알맞은 영상 획득 할 수 있을 것이라 사료된다.