• 한국의류학회지
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• 제12권2호
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• pp.237-248
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• 1988

To access the appropriate height of sleeve cap which is required for the basic sleeve pattern according to arm movements, plaster gypsum experiment was performed. Arm movements were 5types ($0^{\circ},\;45^{\circ},\;90^{\circ},\;135^{\circ},\;180^{\circ}$) to the vertical directions in the front. The appropriateness of the pattern was analyzed by measuring clothing pressure. The results obtained were as follows: 1. Increasing the movement angle, sleeve width increased but height of sleeve cap and armhole girth decreased. 2. Increasing the movement angle, the acromion moved to the front part of bodice. 3. On the basis of the result of the height of sleeve cap, the $\frac{AH}{4} +2.5cm$ sleeve basic 4 pattern is suitable for the direction $M_1(0^{\circ}),\;M_2(45^{\circ})$, and the $\frac{AH}{5}$sleeve basic pattern is suitable for the direction $M_3(90^{\circ}),\;M_4(135^{\circ})$, and $M_5(180^{\circ})$. 4. As the movement angle and height of sleevecap increased, the part which receive high pressure increased and the difference between the hightest and the lowest clothing pressure increased. 5. By the variation of movement angle and height of sleevecap, clothing pressure of upperarm was affected more than that of shoulder blade. 6. The clothing pressure of upperarm and shoulder blades were more affected by the height of sleeve cap than the ease of breast area. 7. Considering the clothing pressure of various arm movement, the most appropriate height of sleeve cap for $M_1(0^{\circ}),\;M_2(45^{\circ})$ positions was to use the $\frac{AH}{4}$+2.5cm, and for $M_3(90^{\circ}),\;M_4(135^{\circ})$, and $M_5(180^{\circ})$, was $\frac{AH}{5}$.

• 소성∙가공
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• 제29권6호
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• pp.331-337
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• 2020

Blind rivet nuts (BRNs) are increasingly used in automotive industry because unlike conventional bolt fastening, BRN fastening requires access from one side only. Generally, fastening is conducted using automated units, but manual fastening may be resorted to in case of small quantities. Since the fastening direction is not exactly perpendicular to the sheet metal, the BRN axis is tilted with respect to the plate and may result in damage or incomplete fastening. As the tilt angle (clamping angle α) increases, undesired plate deformation occurs and the contact area of the plate with the BRN fastening area decreases, reducing the clamping effect. In this study, the reduction of the clamping effect with the α was investigated to ensure stable fastening force. M6 BRNs were used in the tests. The fastening force was measured as follows: the plate was cut in half through the center of the hole; the BRN was inserted into the hole and fastened; and the clamping angle a was measured (values, 0° ≤ α ≤ 9°). The force leading to the separation of the halves was measured using a universal testing machine (UTM). The maximum α range, in which the fastening force remains stable, was determined. Finite element (FE) analysis confirmed that the fastening force decreases approximately linearly with increasing α. Based on the experiment and FE analysis using various α, the fastening force was found to decrease with α. Further, the maximum tolerance for α that provides secure fastening without damage is suggested.

• Restorative Dentistry and Endodontics
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• 제37권2호
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• pp.104-109
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• 2012

Objectives: The purpose of this study was to evaluate the buccolingual curvature at the apical one third in type II mesial canals of mandibular molars using the radius and angle of curvature. Materials and Methods: Total 100 mandibular molars were selected. Following an endodontic access in the teeth, their distal roots were removed. #15 H- or K-files (Dentsply Maillefer) were inserted into the mesiobuccal and mesiolingual canals of the teeth. Radiographs of the teeth were taken for the proximal view. Among them, type II canals were selected and divided into two subgroups, IIa and IIb. In type IIa, two separate canals merged into one canal before reaching the apex and in type IIb, two separate canals merged into one canal within the apical foramen. The radius and angle of curvature of specimens were examined. Results: In type II, mean radius of curvature in mesiolingual and mesiobuccal canals were 2.82 mm and 3.58 mm, respectively. The radius of the curvature of mesiolingual canals were significantly smaller than that of mesiobuccal canals in type II, and especially in type IIa. However, there were no statistically significant differences in radius of curvature between mesiobuccal and mesiolingual canals in type IIb and there were no significant differences in angle of curvature between type IIa and IIb. Conclusion: In this study, type II mesial canals of mandibular molars showed severe curvature in the proximal view. Especially, mesiolingual canals of type IIa had more abrupt curvature than mesiobuccal canals at the apical one third.

• Journal of electromagnetic engineering and science
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• 제4권4호
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• pp.183-189
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• 2004

In this paper, the Eigen-RAKE receiver in wideband direct sequence code-division multiple access(DS-CDMA) systems with downlink smart antenna is analyzed for different spreading bandwidths(1.25 MHz, 5 MHz, 10 MHz) and different channel environments(macro, micro). The realistic spatio-temporal wideband multipath channel is assumed, one of which is standardized multiple-input single-output(MISO) radio channel model for WCDMA link-level simulations proposed by $3^{rd}$ generation partnership project(3GPP) contributions. We assumed spatial scattering phenomenon in which many unresolvable path signals within a limited range of spatial angle simultaneously contribute to the signals received at the receiver. Several multipaths within one chip are distinguished into each one and the first multipath components are selected as the desired signal and the others are considered self-interference. Downlink DS-CDMA system with eigenbeamformer using wider bandwidth present better performance than that using narrow bandwidth system by employing Eigen-RAKE receiver of many number of branches. It is shown that the downlink eigenbeamformer is more effective in typical urban macro cellular environments when using Eigen-RAKE receiver.

• 대한조선학회논문집
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• 제44권2호
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• pp.64-73
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• 2007

Turbulent flows around yacht sails were calculated to access the applicability of CFD for yacht design. Multi-block grid system was generated by using Gridgen package and Fluent was used to calculate flows around two sail system. A 30ft class sailing yacht designed and tested by KRISO was chosen. The interference effect between main and jib sails was analyzed. Pressure distribution on the sails was obtained and the center of effort was estimated. It was found that the jib angle affects the flow phenomena around a main sail due to the change of inflow angle. The location of center of effort is much different from the empirical formula based on a simple geometrical consideration. The calculated results are compared with the previous numerical and experimental results. Both CFD results are similar, but there are some discrepancies with experimental data. However, it is certain that CFD can be a very useful tool for yacht design.

• 한국생산제조학회지
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• 제20권6호
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• pp.773-777
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• 2011

Conventional ultrasonic thickness measurement is to be considered as the assumption that the ultrasonic velocity is known. In actual applications the velocity is often not well known and access is often limited to one side. This paper aims at determining the ultrasonic velocity and thickness of plates with parallel or wedged surfaces using contact measurements made on one surface only. For wedged plates the thickness at one point and the wedge angle are determined. Equations are used for determining the ultrasonic velocity, thickness and wedge angle of the plate based on the times-of-flight measured by two contact transducers coupled to one surface. The time-of-flight of the obliquely reflected longitudinal wave echo was measured as a function of the separation between the two transducers. In addition, a simulation was made for comparing the experimental data and a FEM image. Experiments and simulations were performed on flat and wedged plates of aluminium materials; the calculated results for the unknown quantities are generally agreed with them to some degree.

• Journal of electromagnetic engineering and science
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• 제11권1호
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• pp.34-41
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• 2011

This paper proposes a systematic design for a precoding codebook for a transmit-ing space-division multiple access (TN-SDMA) sharing spectrum with existing fixed wireless service (FWS). Based on an estimated direction angle of a victim FWS system, an interfering transmitter adaptively constructs a codebook, forming a transmit in the direction angle, while satisfying orthogonal beamforming constraints. Sum throughput results indicate that the throughput loss of TN-SDMA relative to a practical SDMA, called per user unitary and rate control ($PU^2RC$), is lower at larger number of transmission antennas, lower signal-to-noise ratio, or a smaller number of users. In particular, a small loss (12% throughput loss) is provided for practical system parameters. Spectrum sharing results confirm that TNSDMA efficiently shares spectrum with FWS systems by reducing protection distance to more than 66 %. Although a TN-SDMA system always has lower throughput compared to $PU^2RC$ in non-coexistence scenarios; it offers an intriguing opportunity to re-use a spectrum already allocated to an FWS.

• Journal of Korean Neurosurgical Society
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• 제41권3호
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• pp.161-165
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• 2007

Objective : Percutaneous approach to the middle thoracic vertebra through the transpedicular route for the patients with osteoporotic vertebral compression fractures is difficult due to the small size of the pedicle and parasagittally oriented vertebra body anatomy. The percutaneous vertebral body access [PVBA] technique utilizing the posterolateral extrapedicular approach avoids the pedicle and provides direct access to the vertebral body. The objective of this study is to evaluate the efficacy of the vertebroplasty utilizing PVBA technique for osteoporotic vertebral compression fractures in the middle thoracic vertebrae. Methods : A retrospective review was done on 20 patients who underwent vertebroplasty utilizing PVBA technique performed for painful osteoporotic compression fracture in the middle thoracic vertebrae at 22 levels from May 2003 to June 2006. The average amount of the injected cement was 1.5-2.5ml. The postprocedural outcome was assessed using a visual analogue scale [VAS]. Results : The treated vertebrae were T5 [1 level], T6 [5 levels], 17 [7 levels], and T8 [9 levels]. The compression rate and kyphotic angle were improved after procedure from $18%{\pm}13.4$ to $16%{\pm}13.8$ [p > 0.05] and from $6.9^{\circ}{\pm}6.7$ to $6.6^{\circ}{\pm}6.2$ [p>005], respectively. Preprocedural VAS was $8.2{\pm}0.70$ and was decreased to $2.1{\pm}1.02$ [p < 0.01] after treatment. Postprocedural cement leakage was noted in 3 levels [13.7%]. There were no cases of leakage to epidural space or neural foramen, segmental artery injury, and pneumothorax. Conclusion : These results suggest that the complication rates are low and good results can be achieved with vertebroplasty utilizing PVBA technique for the osteoporotic vertebral compression fractures especially in the middle thoracic vertebrae.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권6호
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• pp.566-574
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• 2006

Purpose : This study was performed to provide an anatomical information of the mandibular ramus for the successful inferior alveolar nerve block. Three dimensional images were reconstructed from the computerized tomography (CT) and the anatomical evaluation of the mandibular ramus was done. Materials and methods : Sixty-four patients who had been taken the facial CT scans from 2000, Jan to 2003, June was selected. The patients who had the anterior or posterior teeth misssing, edentulous ridge, and jaw fracture were excepted. In the occulusal plane, the lingual surface angle (LSA) between the mid-sagittal plane and the mandibular molar lingual surface from the 2nd premolar to the 2nd molar, the inner ramal surface angle (IRSA), the maximum inner ramal surface angle (MxIRSA), and the outer ramal surface angle (ORSA) to the-mid sagittal plane were measured. The inner ramal surface angle in the ligular tip level (IRSA-L) and the outer ramal surface angle in the ligular tip level (ORSA-L), the ramal length (RL), and the anterior ramal length (ARL) were also measured in the lingular tip level. Results : In the lingular tip level, the mean IRSA-L and ORSA-L were $28.6{\pm}6.3^{\circ}$ and $17.9{\pm}4.9^{\circ}$ respectively. The larger was the IRSA, the larger was the ORSA. In the lingular tip level, the mean ramal length was 35.8${\pm}$3.4 mm. The larger was the IRSA-L, the shorter was the ramal length. On the lingular tip level, the mean anterior ramal length from anterior ramus to lingular tip was 19.6${\pm}$3.3 mm. when the ramal length was longer, the anterior ramal length was also longer. On the lingular tip level, there was positive correlation vetween the IRSA and the ORSA, negative correlation between the IRSA and the ramal length, and positive correlation between the ramal length and the lingular tip level to the anterior ramus. There was no statistical meaning of data between sex and age. Conclusion : In the clinical view of the results so far achieved, if the direction of needle is closer to posterior it is able to contact bone on lingular tip when the internal surface of ramus is wided outer.

• 한국멀티미디어학회논문지
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• 제17권9호
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• pp.1092-1097
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• 2014

It is difficult to perform automatic formation flight of UAV (Unmanned Aerial vehicle) when GPS (Global Positionig System) is out of order or has a system error, since the relative position estimation in the flight group is impossible in that case. In this paper, we design a relative localization system for the automatic formation flight of UAV. For this purpose, we adopt digital beam forming (DBF) to estimate the angle with the central controller of the flight group and Particle Filtering scheme to compensate the estimation error of ToA (time of arrival) method. Computer simulation results present a proper distance between the central controller and a following unit to maintain the automatic formation flight.