• 한국측량학회:학술대회논문집
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• 한국측량학회 2010년 춘계학술발표회 논문집
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• pp.139-140
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• 2010

최근, 세계 각국들은 자국의 해양영토 확보에 총력을 기울이는 가운데, 이로 인한 국가 간의 잦은 분쟁이 유발되고 있어 삼면이 바다인 우리나라의 경우 주변국들과의 분쟁의 소지가 높아 우리나라 해양영토의 확보를 위한 노력이 필요한 시점이다. 따라서 본 연구에서는 해양영토 관할권의 기준이 되는 영해기준점의 실태 조사 및 분석을 통해 효과적이고 종합적인 영해기준점 활용방안을 제시함으로써, 향후 해양영토의 기준 및 해양영토 확장을 위한 기반을 마련하고자 한다.

• 한국통신학회논문지
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• 제38B권10호
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• pp.775-784
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• 2013

이동통신 사업자들은 자신의 망 총소유비용을 줄이면서 데이터 폭증에 대처하기 위한 다양한 기술적인 대책 들을 강구하고 있다. 이 논문에서는 그러한 기술적인 대책의 하나로써 클라우드 기지국이란 새로운 기지국 구조에서 조정 다중점 송수신 운용에 따른 시스템 용량 및 이동성 성능에 관련된 모의실험 결과를 도출한다. 그 결과는 조정 다중점 송수신이 적용되는 클라우드 기지국의 규모 및 적용 영역에 따라 시스템 용량 및 이동성 성능도 개선될 수 있다는 것을 관찰할 수 있었으며 이러한 상호 인과 관계들은 실제 이동통신 사업자의 망 운용에 있어서 하나의 실용적 지침을 제공할 수 있다.

• 인터넷정보학회논문지
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• 제23권5호
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• pp.9-15
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• 2022

본 논문은 매크로 기지국(Macro base station, MBS) 커버리지에 위치한 건물 내부의 밀집된 스몰셀 네트워크 환경에서 매크로 사용자 단말(Macro user equipment, MUE)의 성능향상을 위한 채널 선택 기반 다중점 협력통신(Coordinated multi-point, CoMP) 방법을 제안한다. 제안하는 CoMP 방법에서 건물 내에 위치한 MUE의 성능향상을 위해 스몰셀 기지국(Small-cell base station, SBS)들이 이웃한 MUE에게 간섭을 적게 미치는 방법으로 채널을 선택하고 CoMP가 필요한 MUE에게 적절한 신호를 송신한다. 시뮬레이션 결과에서 제안하는 CoMP 방법이 기존의 랜덤채널할당 기반의 스몰셀 네트워크 방법과 CoMP방법보다 MUE의 성능을 각각 최대 164%와 51%까지 향상시킨다.

• Tribology and Lubricants
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• 제18권4호
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• pp.255-259
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• 2002

The tribological properties of eight different liquid crystals were investigated in a concentrated point contact device and a ball-on-flat contact. For comparison, the same tests were also performed with commercial greases and the corresponding base oils. Under the fully flooded conditions studied, liquid crystals in a concentrated point contact showed lower friction than commercial greases and greater film thickness dependence on rolling speed than grease base oils or greases. Test results also showed that the film thickness and friction were little influenced by the composition of the examined liquid crystals.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권6호
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• pp.421-425
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• 2012

Purpose: The aim of this study is to compare the soft tissue changes of the midfacial area at the repose position and the natural smiling position for the improvement of evaluation and planning in the orthognathic surgery. Methods: The total of 30 subjects, 15 male and 15 female, were included in this study. The metal point landmarks were placed at the cheek, orbital rim, subpupil, and nasal base. The movements of the landmarks were evaluated at the repose position and smiling position in the lateral and posteroanterior cephalograms. Paired t test and correlation analysis were used for the evaluation of the soft tissue changes statistically. Results: In the lateral cephalograms, the cheek point (4.49 mm in female, 4.87 mm in male) showed the most distant movement. All points presented significant movements, except the orbital rim and nasal base point in male. Cheek point presented significant positive correlation between the horizontal and vertical change in male. Subpupil point presented significant positive correlation between horizontal and vertical change in both male and female. In the posteroanterior cephalograms, the nasal base point (5.41 mm in female, 6.30 mm in male) showed the most distant movement. Subpupil point and nasal base point presented significant movements in both female and male. Nasal base point presented significant negative correlation between the horizontal and vertical change in both male and female. In the lateral and posteroanterior cephalograms, the positional changes of all points presented significant positive correlation with each other in both female and male. Conclusion: The cheek point in the sagittal view and the nasal base point in the frontal view showed the most distant movement on smile. In the sagittal view, the subpupil point and cheek point moved anteriorsuperiorly on smile. In the frontal view, the nasal base points moved laterosuperiorly on smile. In both the sagittal and frontal view, the positional changes of all point were highly correlated to each other. These results may be used in the soft tissue references for the treatment planning of the dentofacial deformity patients.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 the technical trends in the world automobile and lubricant market
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• pp.55-62
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• 2002

Significant changes in the performance requirements of finished lubricants is having a pronounced impact on the quality and manufacturing approach for base stocks, the building block for these products. Separation processing is no longer capable of producing high yields of premium base stocks and is rapidly being replaced with hydroprocessing. Isoparaffins are the most desirable component because of their high Viscosity Index, low pour point and excellent stability. This paper will discuss industry trends and the drive towards higher quality base stocks. Manufacturing options are discussed and examples presented to demonstrate the performance of these premium base stocks.

• Journal of Positioning, Navigation, and Timing
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• 제11권4호
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• pp.369-379
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• 2022

In weighted k-nearest neighbor (WkNN)-based Fingerprinting positioning step, a process of comparing the requested positioning signal with signal information for each reference point stored in the fingerprint DB is performed. At this time, the higher the number of matched base station identifiers, the higher the possibility that the terminal exists in the corresponding location, and in fact, an additional weight is added to the location in proportion to the number of matching base stations. On the other hand, if the matching number of base stations is small, the selected candidate reference point has high dependence on the similarity value of the signal. But one problem arises here. The positioning signal can be compared with the repeater signal in the signal information stored on the DB, and the corresponding reference point can be selected as a candidate location. The selected reference point is likely to be an outlier, and if a certain weight is applied to the corresponding location, the error of the estimated location information increases. In order to solve this problem, this paper proposes a WkNN technique including an outlier removal function. To this end, it is first determined whether the repeater signal is included in the DB information of the matched base station. If the reference point for the repeater signal is selected as the candidate position, the reference position corresponding to the outlier is removed based on the clustering technique. The performance of the proposed technique is verified through data acquired in Seocho 1 and 2 dongs in Seoul.

• The Journal of Advanced Prosthodontics
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• 제3권3호
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• pp.136-139
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• 2011

PURPOSE. A new light curing urethane dimethacrylate and a cold curing resin with simpler and faster laboratory procedures may have even improved flexural properties. This study investigated the 3-point flexural strengths and flexural moduli of two alternate base materials. MATERIALS AND METHODS. A cold curing resin (Weropress) and a light curing urethane dimethacrylate base material (Eclipse). Along with Eclipse and Weropress, a high impact resin (Lucitone199) and three conventional base materials (QC 20, Meliodent and Paladent 20) were tested. A 3-point bending test was used to determine the flexural strengths and flexural moduli. The mean displacement, maximum load, flexural modulus and flexural strength values and standard deviations for each group were analyzed by means of one-way analysis of variance (ANOVA) (with mean difference significant at the 0.05 level). Post hoc analyses (Scheffe test) were carried out to determine the differences between the groups at a confidence level of 95%. RESULTS. Flexural strength, displacement and force maximum load values of Eclipse were significantly different from other base materials. Displacement values of QC 20 were significantly different from Lucitone 199 and Weropress. CONCLUSION. The flexural properties and simpler processing technique of Eclipse system presents an advantageous alternative to conventional base resins and Weropress offers another simple laboratory technique.

• International Journal of Control, Automation, and Systems
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• 제6권5호
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• pp.677-688
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• 2008

In this paper, the general problem of impedance control for a robotic manipulator with a moving flexible base is addressed. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base mobile manipulator is rather new and is being considered for first time using singular perturbation and new sliding mode control methods by authors. Initially slow and fast dynamics of robot are decoupled using singular perturbation method. Slow dynamics represents the dynamics of the manipulator with rigid base. Fast dynamics is the equivalent effect of the flexibility in the base. Then, using sliding mode control method, an impedance control law is derived for the slow dynamics. The asymptotic stability of the overall system is guaranteed using a combined control law comprising the impedance control law and a feedback control law for the fast dynamics. As first time, base flexibility was analyzed accurately in this paper for flexible base moving manipulator (FBMM). General dynamic decoupling, whole system stability guarantee and new composed robust control method were proposed. This proposed Sliding Mode Impedance Control Method (SMIC) was simulated for two FBMM models. First model is a simple FBMM composed of a 2 DOFs planar manipulator and a single DOF moving base with flexibility in between. Second FBMM model is a complete advanced 10 DOF FBMM composed of a 4 DOF manipulator and a 6 DOF moving base with flexibility. This controller provides desired position/force control accurately with satisfactory damped vibrations especially at the point of contact. This is the first time that SMIC was addressed for FBMM.

• 대한수학회지
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• 제36권3호
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• pp.567-580
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• 1999

We prove two variants of a base-point-free pencil trick, which are similar in the spirit of the proof, and apply them to the study of special divisors on a smooth plane curve involving a theorem of Max Noether.