• Journal of Positioning, Navigation, and Timing
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• v.4 no.2
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• pp.79-85
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• 2015

Existing Differential GPS (DGPS) pseudorange correction (PRC) generation techniques based on a virtual reference station cannot effectively assign a weighting factor if the baseline distance between a user and a reference station is not long enough. In this study, a virtual reference station DGPS PRC generation technique was developed based on an enhanced inverse distance weighting method using an exponential function that can maximize a small baseline distance difference due to the dense arrangement of DGPS reference stations in South Korea, and its positioning performance was validated. For the performance verification, the performance of the model developed in this study (EIDW) was compared with those of typical inverse distance weighting (IDW), first- and second-order multiple linear regression analyses (Planar 1 and 2), the model of Abousalem (1996) (Ab_EXP), and the model of Kim (2013) (Kim_EXP). The model developed in the present study had a horizontal accuracy of 53 cm, and the positioning based on the second-order multiple linear regression analysis that showed the highest positioning accuracy among the existing models had a horizontal accuracy of 51 cm, indicating that they have similar levels of performance. Also, when positioning was performed using five reference stations, the horizontal accuracy of the developed model improved by 8 ~ 42% compared to those of the existing models. In particular, the bias was improved by up to 27 cm.

• Defense and Technology
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• no.8 s.138
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• pp.16-23
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• 1990

싱가포르 항공사는 프랑스 Aerospatiale Helicopter Division, CATIC(PRC)과 새로운 4~5인승 단발엔진 헬기를 공동 개발하기로 합의하였다. 잠정적으로 P120L이라고 명명된 이 새로운 항공기는 Gazelle이나 Lama 계열로서, Ecureuil 기를 보완하는 것으로 계획되어 있다. 실제 개발은 1990년 말 개념정의단계 완료후에 결정될 것이며, 첫 비행은 1993년, 인도시기는 1996년으로 예정되어 있다. P120L기에는 2가지 형이 있는데, 하나는 민수용이고 또 하나는 고성능 군용기이다. 기체 총 중량은 민수용은 2천kg, 군수용은 2천3백kg이다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.221-228
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• 2011

For service-area-widening and commercialization of DGNSS service, Ministry of Land, Transport and Maritime Affairs is developing a DGNSS service based on VRS using T-DMB. In this study, three PRC generation algorithms are developed for VRS DGNSS and their accuracies were evaluated. Three DGNSS correction generation algorithms are based on inverse distance weighting, 1st- and 2nd- multiple linear regression, and their positioning accuracies were compared in terms of the number of reference stations used for network composition and the algorithm type. As a result, the positioning accuracy of the case of using 16 sites is better than that of 6 sites. And the algorithm using the multiple linear regression showed the best performance. When the positioning accuracy of VRS DGNSS was compared with the traditional single-reference DGNSS, the improvement ratio was 20-23% and 20-36% for the horizontal and vertical directions, respectively.

• Journal of Trauma and Injury
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• v.22 no.2
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• pp.248-253
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• 2009

Purpose: Hemodynamically unstable pelvic fractures represent therapeutic challenges for the trauma team. The authors of this article have studied the clinical profiles of the angiographic intervention population at the emergency department during four years (2005~2009) to develop clinical guidelines for preventing deaths due to multiple trauma and for predicting the prognosis during initial evaluation. Methods: We performed a retrospective review of 34 patients who had undergone angiographic interventions at the emergency department and compared the differences in clinical variables between survivors and non-survivors. Results: Representative values were compared between survivors and non-survivors : RTS (revised trauma score) 7.006 (6.376~7.841) vs. 6.128 (4.298~6.494), PRC (packed red cell) units 5.5 (2.0~11.0) vs. 15 (8.0~18.5), and lactate (mmol/L) 3.0 (1.0~7.0) vs. 8.5 (3.5~10.5). RTS (p<0.01) and PRC units before angiographic interventions (p=0.01) and lactate (p=0.02) had correlations to the final outcomes. Conclusion: The availability of an angiographic suite and persistent hypotension after adequate fluid resuscitation for pelvic trauma are good indications of angiographic intervention for pelvic hemorrhage.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.2
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• pp.171-177
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• 2012

In this paper, we proposed a algorithm and an operation boundary for fault detection of a onboard GNSS receiver. After aircraft exchange corrections computed by an aircraft receiver, a faulty aircraft receiver is detected by checking consistency of correction. For this purpose, PRC residual is used as the test statistic for fault detection of the onboard GNSS receiver. And operation boundaries are set by using DGPS position error increase with respect to the distance from a reference station. If the fault detection is performed by using aircraft only in operation boundary, the more accurate fault detection can be possible.

• Journal of Aerospace System Engineering
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• v.11 no.2
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• pp.35-42
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• 2017

This paper analyzes the intention of the PRC (People's Republic of China) to establish and operate CADIZ to implement the government's maritime policy and strategy and to project its air power in preparation for maritime provocation and contingency, especially over the area where East Asia countries have claimed to have maritime jurisdiction over one another. This paper is also intended to guide the Republic of Korea's response measures for coping with the maritime intention and threat of China by such measures as reinforcing military power, constructing the strategic air base in Jeju, and expanding the present KADIZ.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.1
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• pp.78-82
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• 2001

Background : The coronal incision is versatile surgical approach to upper and middle region of the facial skeletal including the zygomatic arch. The advantages of coronal approach are minimal injury of facial tissue including facial nerve and satisfactory cosmetic result by hidden scar at hair. But wide exposure of scalp, its disadvantages are operation time and massive blood loss. Methods : Thirty patients undergoing elective surgery were divided 3 groups. Group I used only coronal approach, group II used coronal with subciliary approach and group III used coronal with subciliary and intraoral approach. And then retrospected of the preoperative, postoperative red blood cell count, hemoglobin(Hb), hematocrit, transfused red blood cell units and platelet cell units, and the amount of infused crystalloids and colloids, and postoperative hemovac count was estimated. Results: 1. Red blood cell count were decreased in all groups at immediated postoperation and decreased in all group of postoperative first day and decreased in group I, II but increased group III of postoperative third day. 2. Hemoglobin and hematocrit were decreased in all group at immediated postoperation and decreased in all group of postoperative first day and decreased in group I, II., but increased group III postoperative third day. 3. Platelet was decreased in all group at immediated postoperation, and decreased in group II, III but increased in group I of postoperative first day and decreased in group I but increased group II, III of postoperative third day. 4. Mean postoperative hemovac mean drainage group I of first day is $48.63{\pm}21.12ml$ and second day is $23.92{\pm}19.53ml$ and third day is $7.82{\pm}5.32ml$ and group II of first day $60.45{\pm}22.65ml$ and second day is $22.14{\pm}13.21ml$ and third day is $7.32{\pm}6.25ml$. III group of first day $58.16{\pm}10.13ml$ and second day is $21.27{\pm}11.72ml$ and third day is $7.13{\pm}4.90ml$. 5. Infusion of group I is mean PRC $1.08{\pm}0.91$ pint, FFP $1.03{\pm}0.75$ pint, crystalloid $2562.23{\pm}1345.53ml$ and group II is mean PRC $1.05{\pm}0.89$ pint, FFP $1.71{\pm}0.78$, crystalloid $2650.47{\pm}1096.36ml$ and group III is mean PRC $1.79{\pm}1.45$ pint, crystalloid $3295.43{\pm}1472.432ml$.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.4
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• pp.45-50
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• 2006

Copper via filling is the important factor in 3-D stacking interconnection of SiP (system in package). As the packaging density is getting higher, the size of via is getting smaller. When DC electroplating is applied, a defect-free hole cannot be obtained in a small size via hole. To prevent the defects in holes, pulse and pulse reverse current was applied in copper via filling. The holes, $20\and\;50{\mu}m$ in diameter and $100{\sim}190\;{\mu}m$ in height. The holes were prepared by DRIE method. Ta was sputtered for copper diffusion barrier followed by copper seed layer IMP sputtering. Via specimen were filled by DC, pulse and pulse-reverse current electroplating methods. The effects of additives and current types on copper deposits were investigated. Vertical and horizontal cross section of via were observed by SEM to find the defects in via. When pulse-reverse electroplating method was used, defect free via were successfully obtained.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.188-193
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• 2021

In this study, the moisture content of the face skin was changed according to the number of skin applications for female college students under 25 years of age. Moisture contents were measured using a skin moisture meter (skin oil and moisture meter, PRC, China). Skin used 500ml of Innisfree's blueberry rebalancing skin as a clinical trial material. Both the forehead, eyes, cheeks, and chin had a higher moisture content after one layer of application than before and after one layer of application, and after ten layers of application, it can be seen that the moisture content is higher. As a result, when applying basic products after washing your face, the first step is to increase the number of skins, and then apply basic products such as lotion and moisturizing cream to increase the moisture content.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.155-155
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• 2009

The copper plating was deposited by pulse reverse current (PRC) method with additives. The all specimens were first immersted in 10% H2SO4 for 10 minutes, and then were rinsed with deionized water. The current densities of forward pulse were 400mA/$cm^2$, and those of reverse pulse were 1900mA/$cm^2$ and 100mA/$cm^2$. Results are compared for different additives for pulse plating conditions. When it added in Only CH4N2S (TU) or only C10H13NO3S (SVH), the effect of surface side growth of Cu was not different. But when it added in TU and SVH, surface side growth of Cu decreased. Polarization curves were measured from OCP to -0.7 V at a rate of 1mV/sec. Each specimen was observed under the PHENOM to see surface morphology.