• Journal of Communications and Networks
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• v.18 no.2
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• pp.162-172
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• 2016

The placement of the complete baseband processing in a centralized pool results in high data rate requirement and inflexibility of the fronthaul network, which challenges the energy and cost effectiveness of the cloud radio access network (C-RAN). Recently, redesign of the C-RAN through functional split in the baseband processing chain has been proposed to overcome these challenges. This paper evaluates, by mathematical and simulation methods, different splits with respect to network level energy and cost efficiency having in the mind the expected quality of service. The proposed mathematical model quantifies the multiplexing gains and the trade-offs between centralization and decentralization concerning the cost of the pool, fronthaul network capacity and resource utilization. The event-based simulation captures the influence of the traffic load dynamics and traffic type variation on designing an efficient fronthaul network. Based on the obtained results, we derive a principle for fronthaul dimensioning based on the traffic profile. This principle allows for efficient radio access network with respect to multiplexing gains while achieving the expected users' quality of service.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.2
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• pp.87-92
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• 2008

The breakup processes and spray plume characteristics of liquid jets injected in subsonic air cross-flows were experimentally studied. The behaviors of column, penetration, breakup of plain liquid jet and droplet sizes, velocities have been studied in non-swirling cross-flow of air. Nozzle has a 1.0 mm diameter and Lid ratio=5. Experimental results indicate that the breakup point is delayed by increasing air momentum, the penetration decreases by increasing Weber number and the split angle is increased by increasing air velocity or decreasing injection velocity. SMD increases according as increasing height or decreases in accordance with increasing air velocity. This phenomenon is related to the momentum exchange between column waves and cross-flow stream. Droplet vector velocities were varied from 11.5 to 33 m/s. A higher-velocity region can be identified in down edge region at Z/d=40, 70 and 100. Lower-velocity region were observed on bottom position of the spray plume.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.546-555
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• 2013

In this paper, we propose a novel method to enhance the harmonic components from the frequency lines of the passive sonar signals. For this, we first separate the stable frequency lines from unstable ones using mean and difference of spectral bins in the vernier analysis. Then we emphasize the harmonic components using autocorrelation-based postprocessing, and enhance them by reducing the background noise with the split-window two pass mean algorithm. Experimental results for real underwater acoustic data are presented with our discussions.

• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.53-57
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• 2007

In paper, We evaluated for various diode type ESD protection device using TLP measurement method. An Evaluation diode is divided to Enclosed type and Stripe type as pattern style in extensive. These diodes is split up followed factor that Anode-to-Cathod space, N+ region width, Multi type and Contact to Active space. After a TLP measurement, we can be got the Vt2, It2 by I-V characteristic values. In the results, diode of enclosed type is present relatively higher Current capability(It2) than stripe type in a same voltage conditions. And the Second-breakdown voltage(Vt2) were that Stripe type's diode higher than Enclosed type's diode as have $14{\sim}15V$. Finally we suggest the best diode design condition as ESD protection device using entire consequence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.10-18
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• 2014

In this paper, we propose a new frequency reconfigurable dual-band antenna. By using an electronically compact eighth-mode substrate-integrated-waveguide(EMSIW) resonator, we have designed a compact antenna, which performs dual-band movement by additionally loading a complementary split ring resonator(CSRR) structure. The EMSIW and CSRR structures are designed to satisfy the bandwidths of 1.575 GHz(GPS) and 2.4 GHz(WLAN), respectively. We load the CSRR with a varactor diode to allow a narrow bandwidth and to enable the resonance frequency to continuously vary from 2.4 GHz to 2.5 GHz. Thus, we realize a channel selection function that is used in the WLAN standards. Irrespective of how a varactor diode moves, the EMSIW independently resonates so that the antenna maintains a fixed frequency of the GPS bandwidth even at different voltages. Consequently, as the DC bias voltage changes from 11.4 V to 30 V, the resonance frequency of the WLAN bandwidth continuously changes between 2.38 GHz and 2.5 GHz, when the DC bias voltage changes from 11.4 V to 30 V. We observe that the simulated and the measured S-parameter values and radiation patterns are in good agreement with each other.

• Journal of Veterinary Clinics
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• v.25 no.3
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• pp.195-199
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• 2008

A 2-year-old female Maltese dog was referred with primary complaints of exercise intolerance and abnormal heart sound. Clinical and diagnostic investigation revealed split S2 and S4 gallop in the cardiac auscultation, tall P wave and left anterior fascicular block in the electrocardiogram, left atrial enlargement on the thoracic radiography, ostium primum atrial septal defect and cleft of the anterior leaflet of the mitral valve on the echocardiography. Based on those findings, the dog was diagnosed as the partial atrioventricular canal defect. Since the dog showed mild exercise intolerance, enalapril and furosemide were prescribed.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.809-812
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• 2001

본 논문에서는 AMR(Adaptive Multi-Rate)과 MLT (Modulated Lapped Transform) 벡터 양자화 방법을 이용하여 광대역 음성부호화기를 설계하였다. 제안한 음성부호화 알고리즘은 split-band 구조를 가지고 있으며 16kHz로 샘플링 된 신호를 입력받아 QMF 필터에 의해 두 개의 대역으로 나누어, 각각 8kHz 샘플링 신호로 변환시킨 후 저대역(0Hz-3400Hz)의 신호와 고대역(3400Hz -7000Hz)의 신호로 나누어 각각 부호화한다. 나누어진 두 개의 협대역 음성신호는 AMR(Adaptive Multi-Rate)부호화기와 MLT (Modulated Lapped Transform)벡터 양자화 방법을 사용하여 각각 부호화되어 전송된다. 수신단에서는 각 대역을 AMR과 IMLT(Inverse MLT) 벡터 양자화 방법으로 역부호화하여 음성신호를 합성한다. 제안한 음성부호화기는 20.2kbps에서 12.15kbps까지의 다전송률로 동작된다. 설계된 광대역 음성부호화기는 MOS시험 결과로부터 G.722의 56 kbps 음성이 설계된 코더의 20.2 kbps와 비슷한 음질을 갖음을 확인할 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.2
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• pp.184-188
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• 2001

Horner's syndrome as a complication of orthognathic surgery is given little attention of head and neck surgery and is a relatively benign and transient condition. A 18-year-old male referred to our department with long and anteriorly projected chin. The cephalometric evaluation revealed a skeletal Class III relationship. A 10-mm setback of the mandible to eliminate Class III relationship and 4-mm vertical reduction genioplasty were performed. Three weeks after operation, the patient was recognized anhidrosis in left face and the head, and ptosis of left eye. The trauma to cervical sympathetic nerve during left sagittal split ramus osteotomy was thought to be the cause of Horner's syndrome. Patient was treated by dermatologic and opthalmologic care. Follow-up examination 8 months later, he was recovery of horner's symptom.

• Journal of Korean Society of Transportation
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• v.8 no.2
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• pp.77-97
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• 1990

Compared to modal split, the methods of forecasting traffic volumes diverted in various types of I.C.s have not been sufficiently studied. The purpose of this study is to derive a new diversion function that can represent the directional traffic volume in accordance with various geometrics of I.C.s. In general, knowing various traffic impedances and the amount of traffic production and attraction, one can estimate proper traffic volumes associated with directions by using a well-defined diversion function. This function is usually made by a series of process such as surveying directional traffic volumes on several I.C.s, analyzing with a regression method and verifying those results by statistical approaches. The function has been developed by rigorous statistical testings, mainly a regression analysis. This paper presents an effective method in planning and designing new roads, I.C.s and route choice of subway. Finally, some comparisons and improvements and suggested when one uses different types of relevant models and functions.

• Korean Journal of Child Studies
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• v.22 no.3
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• pp.1-15
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• 2001

The development of this inventory for measuring the parenting self-efficacy of Korean mothers took place in Seoul with 473 mothers of 5th and 6th grade children. Means, %, ${\chi}^2$, Cramer's V, Cronbach's ${\alpha}$, Split-half Reliability, factor analysis and Pearson's r were used for data analysis. Five parenting self-efficacy factors were extracted from the 37 items developed for this study. Subscales were General Parenting Self-Efficacy, Health, Communication, Education, and Control. Criterion Validity of the 37 items was confirmed by a significant correlation with the Shin's parenting self-efficacy(r=.71). Internal consistency of this scale was high (Cronbach's ${\alpha}=.92$), including internal reliability of subscales. Factor validity was satisfactory at .65 - .86. These results confirm this scale as a valid and reliable measure of the parenting self-efficacy of Korean mothers.