• 제목/요약/키워드: frequency effect

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Analysis of Parameters Effecting MOBILE WiMAX Connectivity (모바일 WiMAX의 연결성 매개변수 효율 분석)

  • Chowdhury, Olly Roy;Kaiser, Arif;Kabir, Ekramul;Aditya, Subrata Kumar;Park, Jang-Woo
    • Journal of Advanced Navigation Technology
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    • v.18 no.1
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    • pp.84-89
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    • 2014
  • Worldwide Interoperability for Microwave Access (WiMAX) is an efficient technology for 20th century communication system. The technology provides broadband speed without the need for cables and is based on the IEEE 802.16 standard(also called Wireless MAN). Mobile WiMAX is defined as IEEE802.16e which is advanced and efficient technology for mobile telecommunication rather than GSM, CDMA technology. In this work link budget calculation for WiMAX have been done. Cell range have been calculated over digital modulations and they are BPSK, QPSK and QAM. Here different types of models like Cost 231 model have been used for different types of areas like open, rural and urban areas and Erceg-Greenstein model for sub-urban areas. Effect of various parameters like frequency, base station antenna height, transmission power and SNR over cell range have been studied. Analysis have done for both uplink and downlink.

Neuroprotective Effects of Sacral Epidural Neuromodulation Following Spinal Cord Injury : An Experimental Study in Rats

  • Lee, Chang-Hyun;Hyun, Seung-Jae;Yoon, Cheol-Yong;Lim, Jae-Young;Jahng, Tae-Ahn;Kim, Ki-Jeong
    • Journal of Korean Neurosurgical Society
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    • v.52 no.6
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    • pp.509-512
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    • 2012
  • Objective : The purpose of this study is to evaluate neuroprotective effect of sacral neuromodulation in rat spinal cord injury (SCI) model in the histological and functional aspects. Methods : Twenty-one female Sprague Dawley rats were randomly divided into 3 groups : the normal control group (CTL, n=7), the SCI with sham stimulation group (SCI, n=7), and the SCI with electrical stimulation (SCI+ES, n=7). Spinal cord was injured by dropping an impactor from 25 mm height. Sacral nerve electrical stimulation was performed by the following protocol : pulse duration, 0.1 ms; frequency, 20 Hz; stimulation time, 30 minutes; and stimulation duration, 4 weeks. Both locomotor function and histological examination were evaluated as scheduled. Results : The number of anterior horn cell was $12.3{\pm}5.7$ cells/high power field (HPF) in the CTL group, $7.8{\pm}4.9$ cells/HPF in the SCI group, and $6.9{\pm}5.5$ cells/HPF in the SCI+ES group, respectively. Both the SCI and the SCI+ES groups showed severe loss of anterior horn cells and myelin fibers compared with the CTL group. Cavitation and demyelinization of the nerve fibers has no significant difference between the SCI group and the SCI+ES group. Cavitation of dorsal column was more evident in only two rats of SCI group than the SCI+ES group. The locomotor function of all rats improved over time but there was no significant difference at any point in time between the SCI and the SCI+ES group. Conclusion : In a rat thoracic spinal cord contusion model, we observed that sacral neuromodulation did not prevent SCI-induced myelin loss and apoptosis.

The Effects of Stress Related Genes on Carcass Traits and Meat Quality in Pigs

  • Jin, H.J.;Park, B.Y.;Park, J.C.;Hwang, I.H.;Lee, S.S.;Yeon, S.H.;Kim, C.D.;Cho, C.Y.;Kim, Y.K.;Min, K.S.;Feng, S.T.;Li, Z.D.;Park, C.K.;Kim, C.I.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.2
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    • pp.280-285
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    • 2006
  • The current study was conducted to investigate the relationship between stress related gene and meat quality in pigs. A total number of 212 three-way cross bred (Landrace-$Yorkshire{\times}Duroc$) and 38 Duroc were sampled from the Korean pig industry to determine genotype frequency of porcine stress syndrome (PSS) and heat shock protein 70 kDa (HSP70) genes and their relationship with carcass traits and longissimus meat quality. Screen of HSP70 was performed by the single strand conformation polymorphism (SSCP) technique. Based on the analysis of restriction fragment length polymorphism (RFLP) in ryanodine receptor 1 (RYR1) gene, genetic disorder of PSS was related to a mutation at $18,168^{th}$ (C to T) of exon 17. There was no significant difference in ultimate meat pH and backfat thickness between HSP70 K1-AA type and -BB type in pure Duroc breed. In Landrace-$Yorkshire{\times}Duroc$ (L-$Y{\times}D$) cross bred pig, our results indicated that HSP70 derivate type in Duroc had a limited effect on backfat thickness, but L-$Y{\times}D$ type had a noticeable linkage with HSP70 K1-AA and K3-AB. This tendency was also observed in hot carcass weight where HSP70 K1-AA and K3-AB resulted in heavier weight with 86.3 kg compared to HSP70 K1-AB and K3-BB of 74.3 kg. Results imply that stress related HSP70 genotype has a potential association with backfat thickness and carcass weight.

Screening in the Era of Economic Crisis: Misperceptions and Misuse from a Longitudinal Study on Greek Women Undergoing Benign Vacuum-assisted Breast Biopsy

  • Domeyer, Philip John;Sergentanis, Theodoros Nikolaos;Katsari, Vasiliki;Souliotis, Kyriakos;Mariolis, Anargiros;Zagouri, Flora;Zografos, George Constantine
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.9
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    • pp.5023-5029
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    • 2013
  • Background: To evaluate knowledge about screening tests and tests without proven screening value in a Greek Breast Unit population undergoing benign vacuum-assisted breast biopsy (VABB). Materials and Methods: This study included 81 patients. Three knowledge-oriented items (recommended or not, screening frequency, age of onset) were assessed. Regarding screening tests two levels of knowledge were evaluated: i). crude knowledge (CK), i.e. knowledge that the test is recommended and ii). advanced knowledge (AK), i.e. correct response to all three knowledge-oriented items. Solely CK was evaluated for tests without proven screening value. Risk factors for lack of knowledge were assessed with multivariate logistic regression. A second questionnaire was administered 18 months after VABB to assess its impact on the performance of tests. Results: Concerning screening tests considerable lack of AK was noted (mammogram, 60.5%; Pap smear, 59.3%; fecal occult blood testing, 93.8%; sigmoidoscopy, 95.1%). Similarly lack of CK was documented regarding tests without proven screening value (breast self-examination, 92.6%; breast MRI, 60.5%; abdominal ultrasound, 71.6%; barium meal, 48.1%; urine analysis, 90.1%; chest X-Ray, 69.1%; electrocardiogram, 74.1%; cardiac ultrasound, 75.3%). Risk factors for lack of AK were: place of residence (mammogram), age (Pap smear), personal income (sigmoidoscopy); risk factors for lack of CK included number of offspring (breast MRI, chest X-Ray), BMI (abdominal ultrasound), marital status (urine analysis), current smoking status (electrocardiogram). VABB's only effect was improvement in mammogram rates. Conclusions: A considerable lack of knowledge concerning screening tests and misperceptions regarding those without proven value was documented.

Adaptive Enhancement Algorithm of Perceptual Filter Using Variable Threshold (가변 임계값을 이용한 지각 필터의 적응적인 음질 개선 알고리즘)

  • 차형태
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.6
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    • pp.446-453
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    • 2004
  • In this paper, a new adaptive perceptual filter using variable threshold to enhance audio signals degraded by additively nonstationary noise is proposed. The adaptive perceptual filter updates variable threshold each time according to the power of signal and the effect of noise variation. So the noisy audio signal is enhanced by the method which controls a residual noise effectively. The proposed algorithm uses the perceptual filter which transforms a time domain signal into frequency domain and calculates an intensity energy and an excitation energy in bark domain. In this method. the stage updated the response of filter is decided by threshold. The proposed algorithm using vairable threshold effectively controls a residual noise using the energy difference of audio signals degraded by the additive nonstationary noise. The proposed method is tested with the noisy audio signals degraded by nonstationary noise at various signal -to-noise ratios (SNR). We carry out NMR and MOS test when the input SNR is 15dB. 20dB. 25dB and 30dB. An approximate improvement of 17.4dB. 15.3dB, 12.8dB. 9.8dB in NMR and enhancement of 2.9, 2.5, 2.3, 1.7 in MOS test is achieved with the input signals. respectively.

An Empirical Study on Key Factors Affecting Churn Behavior with the Voices of Contact Center Customers (고객센터 상담내용 분석을 통한 이탈 요인에 관한 실증 연구)

  • Jang, Moonkyoung;Yoo, Byungjoon;Lee, Jaehwan
    • The Journal of Society for e-Business Studies
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    • v.22 no.4
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    • pp.141-158
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    • 2017
  • Along with IT development, customers are getting more easily to express their opinions using various IT channels. In this situation, complaint management is a pressing issue for companies to acquire and maintain loyal customers with low cost. Most of previous studies have investigated customer complaint information by quantitative variables such as demographic information, transaction information, or complaint frequency, but studies focusing on qualitative aspects of complaint information are limited. Therefore, this paper considers the possibility for customers to leave even when they complain occasionally or briefly. This paper analyzes the quantitive aspects as well as the qualitative aspects using sentiment analysis with Exit-voice theory. The dataset contains 268,364 inquiries of 46,235 customers obtained from a contact center of a private security company in Korea. This paper carries out logistic regression and the results imply that the customers's explicit response and their implicit sentiment have different effect on customers leave. This study is expected to provide useful suggestions for the effective complaint management.

A Systematic Review of Randomized Controlled Trials on Acupuncture Treatment for Low Back Pain Based on FEAS (요통에 대한 침치료 무작위대조군임상연구(RCT)의 FEAS 분석을 통한 계통적 분석 연구)

  • Nam, Dong-Woo;Kang, Jung-Won;Kim, Eun-Jung;Kim, Hyun-Wook;Song, Ho-Sueb;Kim, Sun-Woong;Kim, Kap-Sung;Lee, Geon-Mok;Choi, Dong-Young;Lee, Jae-Dong
    • Journal of Acupuncture Research
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    • v.26 no.3
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    • pp.133-147
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    • 2009
  • Objectives : To review RCTs on acupuncture treatment for low back pain in order to establish a standard acupuncture treatment model in treating low back pain. Methods : RCT articles on traditional acupuncture treatment for low back pain were searched through online database. Study Quality was assessed using the FEAS. Results : Ten out of the one hundred six articles searched were reviewed. Among the ten articles reviewed, six articles compared acupuncture treatment with no treatment or non-penetrating sham acupuncture. All six articles concluded significantly positive effect of acupuncture compared to the control. Conclusions : The ideal acupuncture treatment model for low back pain was obtained as follows. A sterile disposable stainless steel(0.30mm${\times}$40mm) should be inserted to more than six acupuncture points on the BL, GV and GB meridians such as $BL_23$, $BL_25$, $BL_40$, $BL_60$, $GV_4$ and $GB_30$. Sparrow pecking method to obtain 'de-qi' is recommended and repeated stimulation during the 20 minute retention time is necessary. Ideal treatment frequency would be more than one a week for about 7 weeks.

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A study of variation level for each region changed in trunk at sagittal plane after Trunk Flexion-Extension Exercise (체간 굴곡-신전운동 후 체간 각 부위 별 시상면 높이변화에 대한 조사)

  • Kim, Keun-Jo;Lee, Cu-Rie;Jung, Byeong-Ok
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.14 no.2
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    • pp.1-15
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    • 2008
  • Purpose : This survey was to investigate on the effect of each region changed in trunk through sagittal plane after Trunk Flexion-Extension Exercise. Methods : 18 students of Gimcheon College participated in this study for the period of July 9-30, 2007. Analyzed factor were 1) degree of pain 2) presence of Gillet test and 3) difference of right-left for 7 landmark region in trunk applying I.B.S.-2000 after Trunk Flexion - Extension Exercise. We used the SPSS $PC^+$ program for classifying into analysis of frequency, $x^2$-test, t-test and Simple Linear Regression analysis test. Results: Followings are concluded For degree of pain, 13(72.2%) of students answered "No pain" after Trunk Flexion-Extension Exercise and in the result 4 more students decreased the pain. In the Gillet test, 14(77.8%) of students answered "positive" after Trunk Flexion-Extension Exercise and in the result 4 more students increased mobility of Sacroiliac joint. In the differences of right-left for 7 landmark region in trunk by B.M.I. scale, Slim type was decreased both Acromion(0.45mm), both Iliac crest(0.44mm), and both ASIS(0.31mm) to anterior plane, Normal type was decreased both inferior angle of Scapular(0.02mm), both L4-5(0.07mm), and both PSIS(0.09mm) to posterior plane Fatness type was decrease both Acromion(0.05mm), both ASIS(0.05mm) to anterior plane. In the differences of right-left for 7 landmark region in trunk for degree of pain No pain group was decreased both Acromion(0.17mm), both Nipple(0.25mm) to anterior plane and both PSIS(0.13mm) to posterior plane Pain group was decreased both Acromion(0.04mm), both Iliac creast(0.03mm) to anterior plane and both inferior angle of Scapular(0.18mm) both PSIS(0.13mm) to posterior plane. In the difference of right-left for 7 landmark region in trunk for each of the exercises, Both iliac crest(0.1mm), both ASIS(0.12mm) to anterior plane were decreased after Flexion Trunk Exercise. Both acromion(0.27mm) to anterior plane, both inferior angle of scapular(0.14mm) and both PSIS(0.12mm) to posterior plane were decreased after Extension Trunk Exercise. Each of the exercises, The both inferior angle of Scapular showed high scores($0.65{\pm}0.23$) at Trunk Extension Exercise group and there was statistical significance between Trunk Flexion Exercise group and Extension exercise group(t :-2.502, p < 0.05). 7. At Pre-exercise group, Both inferior angle of Scapular showed low scores($0.23{\pm}8.27$) at Trunk Extension Exercise group and there was statistical significance between Pre- Exercise group and Trunk Extension Exercise group(t :-2.5430, p<0.05). Conclusion : The simple linear regression analysis was presented at Acromion(-0.243), L4-5(-0.753), PSIS(0.576) and there was statistical significance in BMI scale(p<0.01).

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The development of a taste education program for preschoolers and evaluation of a program by parents and childcare personnel

  • Shon, Choengmin;Park, Young;Ryou, Hyunjoo;Na, Woori;Choi, Kyungsuk
    • Nutrition Research and Practice
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    • v.6 no.5
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    • pp.466-473
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    • 2012
  • The change in people's dietary life has led to an increase in an intake of processed foods and food chemicals, raising awareness about taste education for preschoolers whose dietary habits start to grow. This study aims to evaluate the effectiveness and satisfaction of parents and childcare personnel after developing a taste education program and demonstrating it in class. A part of the curriculum developed by Piusais and Pierre was referred for the program. After educating 524 preschoolers in child care facilities in Seoul, a satisfaction survey was conducted on the program. The data in this study were analyzed using SPSS 14.0. Statistical analysis was conducted based on the frequency after collecting the data. Mean ${\pm}$ SD used to determine satisfaction with taste education, with preferences marked on a five-point scale and the alpha was set at 0.05. The program includes five teachers' guides with subjects of sweetness, saltiness, sourness, bitterness and harmony of flavor, and ten kinds of teaching tools. For the change in parents' recognition of the need for taste education based on five-point scale, the average of $4.06{\pm}0.62$ before the program has significantly increased to $4.32{\pm}0.52$ (P < 0.01). Regarding the change in the preferences for sweetness, saltiness, sourness, and bitterness, the average has increased to $3.83{\pm}0.61$, $3.62{\pm}0.66$, $3.64{\pm}0.66$, and $3.56{\pm}0.75$ respectively. In an evaluation of instructors in child care facilities, the average scores for education method, education effect, education contents and nutritionists, and teaching tools were at $4.15{\pm}0.63$, $3.91{\pm}0.50$, $4.18{\pm}0.50$, and $3.80{\pm}0.56$ respectively. In addition, the need for a continuous taste education scored $4.42{\pm}0.67$. This program has created a positive change in preschoolers' dietary life, therefore the continuation and propagation of the taste education program should be considered.

The Study on Wound Healing in Rabbit Skins by Low-intensity Laser Irradiation (저강도 레이저 조사에 의한 가토 피부의 상처 치유에 관한 연구)

  • 김식현;전진석
    • Biomedical Science Letters
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    • v.6 no.2
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    • pp.119-129
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    • 2000
  • The skin is an organ that has many important roles, including protection against infection, regulation of temperature and fluid loss, and sensory function. Injury to the skin, wound repair normally involves: (1) balanced activity of inflammation, (2) the re-epithelial phase and (3) the matrix formation of remodeling phase. Thus, skin wound healing is a finely controlled biological process involving a series of complex cellular interactions. Laser therapy is being implemented with increasing frequency in medicine. Low intensity laser is one that is capable of producing an energy density so low that any biologic alterations are the result of direct irradiation effect, not thermal events. This study was designed to evaluate the efficacy of low intensity laser therapy on skin wound healing in rabbits. A total of 10 male rabbits (New Zealand White Rabbit), age 8 weeks were used. Skin wound were surgically created dorso-lateral on the flank of 10 rabbits (2$\times$2 cm/damage areas). The experimental animals were treated with 5Hz (830 nm wave length) low-intensity laser (MILTA-01 Model) daily for 10 min (1.6 J/$cm^2$) for 12 days. Control animals were sham treated with the laser head. Laser irradiation animals showed a complete remodeling of the epithelial layer, a positive repair of connective tissues, and enhanced the wound closure rate over time as compared to the control animals. Especially, laser irradiation groups improved fibroblast activity, cellular content, granulation tissue formation, and collagen deposition which is resulted in improving the tensile strength of the wound. These findings suggest that laser photostimulation could accelerate healing of open wound in rabbits, and may be benefit in the treatment of open wound, including decubitis ulcers.

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