• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.4
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• pp.73-80
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• 2005

In general, the performance of movable nozzle used for thrust vector control in solid rocket motor is estimated on the basis of the effective pivot of nozzle. However, it is nearly impossible to define the exact effective pivot by the mathematical model or experimental technique owing to pivot dynamics. In this paper, pivot dynamic properties were investigated by ADAMS simulation technique and trajectory of the exact effective pivot was modelled by the artificial neural network. Comparison of the proposed method was made with the virtual movable nozzle (computer simulation) to verify the method, and showed good agreement. Therefore, the proposed method will be applicable to predict the effective pivot of movable nozzle during bench or ground test.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.4
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• pp.30-35
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• 2009

Effective-pivot effects on the thrust vector control performance of the flexible seal nozzle to be used to control the flight direction of missile were investigated by computer simulation. $2^3$-Design of experiment technique was applied and ADMAS was used for the surrogate technique. As a result, radial pivot position had more influence upon the nozzle actuating performance than axial pivot position. Connecting method of actuator was also important factor in determining effective-pivot effects on the thrust vector control performance of the flexible seal nozzle.

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.287-294
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• 2011

Purpose: Reduction malarplasty is one of the common aesthetic procedures performed in the Orient. We have analyzed effective operative methods according to the pivot point for the osteotomy and reposition of the zygoma for reduction malarplasty after confirming the shapes of the individual zygomas. Methods: Thirty-six patients had been received malarplasty over the last 10 years. The average follow-up period was 16 months. We categorized the patients into three groups according to their prominent appearance features. Group I had a prominently protruded zygomatic body, group II had a prominently protruded zygomatic arch, and group III had a prominently protruded body and zygomatic arch. In the group I, two parallel oblique osteotomies on the body, the middle portion was removed, and with the zygomatic arch as the pivot point, the body was repositioned inwards. In the group II, the zygomatic body and arch osteotomy is performed, with the body as the pivot point, and the arch is depressed medially. In the group III, using the two aforementioned methods, the zygoma was repositioned medially. In each case, postoperative complications and patients satisfaction over the surgery were surveyed. Results: Each group had 25, 5 and 12 patients respectively. No significant complications were found except for one patient who experienced a non-union of zygomatic bone. In the case of group I, four patients underwent a secondary operation. Conclusion: Reduction malarplasty is popular as an effective facial contouring surgery. In order to obtain more effective results,however, the zygomatic shape should be identified, and appropriately repositioned by different operative technique according to pivot points.

• Journal of Korean Medical classics
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• v.32 no.2
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• pp.33-47
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• 2019

Objectives : To review the meaning of Open-Close-Pivot and its transition over time. Methods : Annotations and explanations in chapters where the theory of Open-Close-Pivot originated from in the "Suwen(素問)" and "Lingshu(靈樞)" were examined, followed by philological examination of key physicians. Results & Conclusions : Yang Shang Shan(楊上善) compared the 'Open-Close-Pivot' to a door. Wang Bing(王冰) explained it's movement and stillness to be the principle behind the Three-Yin-Three-Yang's threefold division. Wang Ji(汪機), in "XuSuwenChao(續素問鈔)" explained its physiological function as the entering and exiting of Ying Wei(營衛), and its scope to be exterior, interior, and center. Ma Shi(馬蒔) stratified it similar to "Shanghanlun(傷寒論)"'s six stages, while Wu Kun(吳崑) categorized Shaoyang(少陽) as being in-between exterior and interior. Zhang Jing Yue(張景岳) suggested a standard for the entering-exiting and exterior-interior-center concepts of the Open-Close-Pivot. Zhang Zhi Cong(張志聰) argued a theory of Open-Close-Pivot that emphasized the meaning of Three-Yin-Three-Yang, while Gao Shi Zong(高士宗) explained the relationship between Open, Close, Pivot and the functioning process. Shi Shou Tang(石壽棠) explained the physiology and pathology in the actions among Open-Close-Pivot with a focus on Pivot. Ke Qin(柯琴) applied Open-Close-Pivot to "Shanghanlun(傷寒論)" and used it as the basic principle to the Six Channel Ground Theory(六經地面說), also clinically applying it in the identification and treatment of the Six Channel patterns. Conclusions : Counting based word embedding methods seems to be more effective than.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.745-752
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• 2012

The pivot steering of an individual wheel motor drive vehicle is an effective steering maneuver in the narrow road, but it has become a matter of concern that the torque input of each wheel is very difficult to determine. In this study, the independent yaw moment control was proposed for the smooth pivot steering control of an in-wheel drive vehicle. For this control method, the vertical forces of tires were estimated from the trailing arm dynamic model, and the yaw moments of individual wheels were calculated from the vehicle dynamic model. Dynamic simulation results showed that the independent yaw moment control was much more effective on the minimization of the instabilities of pivot steering in comparison with the conventional direct yaw moment control with yaw rate feedback.

• Journal of KIISE:Software and Applications
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• v.41 no.7
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• pp.492-500
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• 2014

This paper presents the performance enhancement of automatic bilingual lexicon extraction by using refinement of pivot-context vectors under the standard pivot-based approach, which is very effective method for less-resource language pairs. In this paper, we gradually improve the performance through two different refinements of pivot-context vectors: One is to filter out unhelpful elements of the pivot-context vectors and to revise the values of the vectors through bidirectional translation probabilities estimated by Anymalign and another one is to remove non-noun elements from the original vectors. In this paper, experiments have been conducted on two different language pairs that are bi-directional Korean-Spanish and Korean-French, respectively. The experimental results have demonstrated that our method for high-frequency words shows at least 48.5% at the top 1 and up to 88.5% at the top 20 and for the low-frequency words at least 43.3% at the top 1 and up to 48.9% at the top 20.

• Steel and Composite Structures
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• v.8 no.6
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• pp.441-455
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• 2008

This paper presents an effective hysteretic model for the prediction and evaluation of steel reinforced concrete member seismic performance. This model adopts the load-deformation relationship acquired from monotonic load tests and incorporates the double-pivot behavior of composite members subjected to cyclic loads. Deterioration in member stiffness was accounted in the analytical model. The composite member performance assessment control parameters were calibrated from the test results. Comparisons between the cyclic load test results and analytical model validated the proposed method's effectiveness.

• The KIPS Transactions:PartD
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• v.14D no.2
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• pp.157-168
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• 2007

For effective analyses in various business applications, OLAP(On-Line Analytical Processing) systems represent the multidimensional data as the horizontal format of tables whose columns are corresponding to values of dimension attributes. Because the traditional RDBMSs have the limitation on the maximum number of attributes in table columns(MS SQLServer and Oracle permit each table to have up to 1,024 columns), horizontal tables cannot be directly stored into relational database systems. In this paper, we propose various efficient optimization strategies in transforming horizontal queries to equivalent vertical queries. To achieve this goral, we first store a horizontal table using an equivalent vertical table, and then develop various query transformation rules for horizontal table queries using the PIVOT operator. In particular, we propose various alternative query transformation rules for the basic relational operators, selection, projection, and join. Here, we note that the transformed queries can be executed in several ways, and their execution times will differ from each other. Thus, we propose various optimization strategies that transform the horizontal queries to the equivalent vertical queries when using the PIVOT operator. Finally, we evaluate these methods through extensive experiments and identify the optimal transformation strategy when using the PIVOT operator.

• Earthquakes and Structures
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• v.12 no.4
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• pp.425-436
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• 2017

Vibration control using a tuned mass damper (TMD) is an effective technique that has been verified using analytical methods and experiments. It has been applied in mechanical, automotive, and structural applications. However, the damping of a TMD cannot be adjusted in real time. An excessive mass damper stroke may be introduced when the mass damper is subjected to a seismic excitation whose frequency content is within its operation range. The semi-active tuned mass damper (SATMD) has been proposed to solve this problem. The parameters of an SATMD can be adjusted in real time based on the measured structural responses and an appropriate control law. In this study, a stiffness-controllable TMD, called a leverage-type stiffness-controllable mass damper (LSCMD), is proposed and fabricated to verify its feasibility. The LSCMD contains a simple leverage mechanism and its stiffness can be altered by adjusting the pivot position. To determine the pivot position of the LSCMD in real time, a discrete-time direct output-feedback active control law that considers delay time is implemented. Moreover, an identification test for the transfer function of the pivot driving and control systems is proposed. The identification results demonstrate the target displacement can be achieved by the pivot displacement in 0-2 Hz range and the control delay time is about 0.1 s. A shaking-table test has been conducted to verify the theory and feasibility of the LSCMD. The comparisons of experimental and theoretical results of the LSCMD system show good consistency. It is shown that dynamic behavior of the LSCMD can be simulated correctly by the theoretical model and that the stiffness can be properly adjusted by the pivot position. Comparisons of experimental results of the LSCMD and passive TMD show the LSCMD with less demand on the mass damper stroke than that for the passive TMD.

• The KIPS Transactions:PartD
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• v.16D no.4
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• pp.463-474
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• 2009

To analyze multidimensional data conveniently and efficiently, OLAP (On-Line Analytical Processing) systems or e-business are widely using views in a horizontal form to represent measurement values over multiple dimensions. These views can be stored as materialized views derived from several sources in order to support accesses to the integrated data. The horizontal views can provide effective accesses to complex queries of OLAP or e-business. However, we have a problem of occurring maintenance of the horizontal views since data sources are distributed over remote sites. We need a method that propagates the changes of source tables to the corresponding horizontal views. In this paper, we address incremental maintenance of horizontal views that makes it possible to reflect the changes of source tables efficiently. We first propose an overall framework that processes queries over horizontal views transformed from source tables in a vertical form. Under the proposed framework, we propagate the change of vertical tables to the corresponding horizontal views. In order to execute this view maintenance process efficiently, we keep every change of vertical tables in a differential file and then modify the horizontal views with the differential file. Because the differential file is represented as a vertical form, its tuples should be converted to those in a horizontal form to apply them to the out-of-date horizontal view. With this mechanism, horizontal views can be efficiently refreshed with the changes in a differential file without accessing source tables. Experimental results show that the proposed method improves average performance by 1.2$\sim$5.0 times over the existing methods.