• Title/Summary/Keyword: Multiple Effect

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Multiple-Period Repetitive Controller for Selective Harmonic Compensation with Three-Phase Shunt Active Power Filter

  • Zhang, Chao;Gong, Maofa;Zhang, Yijun;Li, Yuxia
    • Journal of Power Electronics
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    • v.15 no.3
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    • pp.819-829
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    • 2015
  • This paper presents a shunt active power filter (SAPF) for compensating inter-harmonics and harmonics when inter-harmonics content is evident in the grid. The principle of inter-harmonics generation in the grid was analyzed, and the inter-harmonics effect on repetitive controllers was discussed in terms of control performance. Traditional repetitive controllers are not applicable in inter-harmonic compensation. Moreover, the effect of an ideal controller on harmonics signals was analyzed on the basis of the internal model principle. The repetitive controller was improved in the form of a basis function according to theoretical analysis. The finite-dimensional repetitive controller, which is also called the multiple-period repetitive controller, was designed for the control of multiple periodic signals. A selective harmonic compensation system was developed with SAPF. This system can be used to compensate harmonics and inter-harmonics in the grid. Finally, system control performance was verified by simulation and experimental results.

Optimization of Code Combination in Multi-Code Ultrasonic Sensors for Multi-Robot Systems (군집로봇을 위한 다중 코드 초음파센서의 코드조합 최적화)

  • Moon, Woo-Sung;Cho, Bong-Su;Baek, Kwang Ryul
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.7
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    • pp.614-619
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    • 2013
  • In multi-robot systems, ultrasonic sensors are widely used for localization and/or obstacle detection. However, conventional ultrasonic sensors have a drawback, that is, the interference problem among ultrasonic transmitters. There are some previous studies to avoid interferences, such as TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access). In multiple autonomous mobile robots systems, the Doppler-effect has to be considered because ultrasonic transceivers are attached to the moving robots. To overcome this problem, we find out the ASK (Amplitude Shift Keying)-CDMA technique is more robust to the Doppler-effect than the BPSK (Binary Phase Shift Keying)-CDMA technique. In this paper, we propose a new code-expression method and a Monte-Carlo based algorithm that optimizes the ultrasonic code combination in the ASK-CDMA ultrasonic system. The experimental results show that the proposed algorithm improves the performance of the ultrasonic multiple accessing capacity in the ASK-CDMA ultrasonic system.

A Clinical Case Report on Multiple Sclerosis Treated by Korean Medicine (다발성 경화증에 대한 한방치료 치험 1례)

  • Jeon, Yong-Tae;Park, Sang-Hun;Ko, Youn-Seok
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.9 no.2
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    • pp.21-33
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    • 2014
  • Objectives : This study was to report the improvement of the patient with multiple sclerosis treated by Korean Medical treatment. Methods : The patient diagnosed as multiple sclerosis treated by acupuncture, bee venom pharmacupuncture, chuna manual therapy, and herbal medicine. To evaluate the effects of korean medicine, we used manual muscle test(MMT), the standard for assessment of the effect of stroke treatment, functional system(FS), visual analog scale(VAS). Results : 1. The patient's pain and optic dysfunction were reduced by the above therapy. 2. There was no change in manual muscle test(MMT), but there was mild improvement in finger joints function in the standard for assessment of the effect of stroke treatment. 3. In functional system(FS) scale, there was enhancement in optic function within a range. And there was improvement in expanded disability statue scale(EDSS) from 4.0 to 3.0. 4. In visual analog scale(VAS), there was considerable improvement from 9 to 6. Conclusions : The korean medical treatment was reduced pain and optic dysfunction.

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Effect of Injection Strategy on the Exhaust Emission and Performance Characteristics of a Light-duty Diesel Engine (승용 디젤 엔진에서 분사 전략이 배출 가스 및 엔진 성능에 미치는 영향에 관한 연구)

  • Roh, Hyun-Gu;Lee, Doo-Jin;Lee, Chang-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.3
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    • pp.99-105
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    • 2011
  • This paper described the effect of the multiple injections on the emission characteristics and combustion stability in a common rail diesel engine. In order to investigate the influence of multiple injections in a passenger car diesel engine, the injection strategy was varied with pilot injection, post injection and one main injection at various conditions. Based on the experimental results, the combustion and emissions characteristics were analyzed for the various injection strategies such as main, pilot-main, double-pilot-main, double- pilot-main-post injection strategy. It is revealed that the $NO_X$, HC and CO emissions are reduced by double pilot and post injection at medium load, however, soot emission is increased. Also, in the case of multiple injection, the combustion pressure is increased smoothly near the TDC and the coefficient of variation and fuel consumptions are decreased.

Coalescence Pressure of Steam Generator Tubes with Two Different-Sized Collinear Axial Through-Wall Clacks (길이가 다른 두 개의 축방향 관통균열이 동일선상에 존재하는 증기발생기 세관의 균열 합체 압력)

  • Huh Nam-Su;Chang Yoon-Suk;Kim Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.10 s.253
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    • pp.1255-1260
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    • 2006
  • To maintain the structural integrity of steam generator tubes, 40% of wall thickness plugging criterion has been developed. The approach is for the steam generator tube with single crack, so that the interaction effect of multiple cracks can not be considered. Although, recently, several approaches have been proposed to assess the integrity of steam generator tube with two identical cracks whilst actual multiple cracks reveal more complex shape. In this paper, the coalescence pressure of steam generator tube containing multiple cracks of different length is evaluated based on the detailed 3-dimensional (3-D) elastic-plastic finite element (FE) analyses. In terms of the crack shape, two collinear axial through-wall cracks with different length were considered. Furthermore, the resulting FE coalescence pressures are compared with FE coalescence pressures and experimental results for two identical collinear axial through-wall cracks to quantify the effect of crack length ratio on failure behavior of steam generator tube with multiple cracks. Finally, based on 3-D FE results, the coalescence evaluation diagrams were proposed.

Splinted and non-splinted implant-supported restorations : prosthetic considerations for restoring multiple adjacent teeth (Splinted or Non-splinted: 다수의 인접한 치아 결손부 수복을 위한 임플란트 보철)

  • Yoon, Hyung-In
    • The Journal of the Korean dental association
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    • v.54 no.3
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    • pp.198-205
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    • 2016
  • The purpose of this paper was to investigate the significance of splinted and non-splinted implant-supported restorations with an internal connection for multiple consecutively missing teeth. Upon examination of the effects of fixture-abutment connection, the distribution of occlusal load was favorable in splinted implant-prosthesis with an external connection, but effect of strain distribution was not significant in splinted implant-prosthesis with an internal connection. In splinted implant-prostheses for short implants, strain distribution was not affected by the method of retention. For cement-retained prostheses, the effect of strain distribution due to splinting was not significant. In clinical studies, non-splinted prostheses with an internal connection for multiple consecutively missing teeth showed high survival rate, mild marginal bone loss, and stable periodontal condition. However, failure to achieve optimal proximal contact between single-unit prostheses may lead to food impaction, and veneer fracture may be inevitable when the framework provides inadequate support in the proximal region. In conclusion, splinted implant-prosthesis is not an indication in all cases, and clinical consideration of its use should be based on the patient's oral condition, such as location and number of implants, formation of proximal contact, canine guidance, existence of parafunctional habit, and oral hygiene, when multiple consecutively missing teeth are replaced by internal connection type implant.

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Effect of an Inpatient Rehabilitation Program for Recovery of Deconditioning in Hematologic Cancer Patients After Chemotherapy

  • Cha, Seungwoo;Kim, Inho;Lee, Shi-Uk;Seo, Kwan Sik
    • Annals of Rehabilitation Medicine
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    • v.42 no.6
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    • pp.838-845
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    • 2018
  • Objective To investigate the effect of a rehabilitation program in terms of De Morton Mobility Index (DEMMI) score, in hematologic cancer patients after chemotherapy. Methods Hematologic cancer patients admitted for chemotherapy were reviewed. They received a rehabilitation program during their hospital stay. DEMMI score measurement was performed, before and after rehabilitation. Demographics, diagnosis, chemotherapy information, rehabilitation program duration, mortality, body mass index (BMI), and laboratory test results were collected. For analysis, patients were classified according to diagnosis (multiple myeloma, leukemia, and others), mortality, and additional chemotherapy. Results There was statistically significant improvement in DEMMI score of 10.1 points (95% confidence interval, 5.9-14.3) after rehabilitation. It was more evident in the multiple myeloma group, and they revealed less mortality. When patients were divided according to mortality, survivors received the program earlier, and in a shorter period than in mortality cases. Although survivors revealed higher initial DEMMI score, improvement after rehabilitation did not differ significantly. Conclusion In hematologic cancer patients, rehabilitation program was effective for recovery from deconditioning, revealing significant increase in DEMMI score. Multiple myeloma patients may be good candidates for rehabilitation. Rehabilitation could be sustained during chemotherapy and for high-risk patients.

An Effective Threat Evaluation Algorithm for Multiple Ground Targets in Multi-target and Multi-weapon Environments

  • Yoon, Moonhyung;Park, Junho;Yi, Jeonghoon
    • International Journal of Contents
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    • v.15 no.1
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    • pp.32-38
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    • 2019
  • In an environment where a large number of weapons are operated compared to a large number of ground targets, it is important to monitor and manage the targets to set up a fire plan, and through their multilateral analysis, to equip them with a priority order process for targets having a high threat level through the quantitative calculation of the threat level. Existing studies consider the anti-aircraft and anti-ship targets only, hence, it is impossible to apply the existing algorithm to ground weapon system development. Therefore, we proposed an effective threat evaluation algorithm for multiple ground targets in multi-target and multi-weapon environments. Our algorithm optimizes to multiple ground targets by use of unique ground target features such as proximity degree, sorts of weapons and protected assets, target types, relative importance of the weapons and protected assets, etc. Therefore, it is possible to maximize an engagement effect by deducing an effective threat evaluation model by considering the characteristics of ground targets comprehensively. We carried out performance evaluation and verification through simulations and visualizations, and confirmed high utility and effect of our algorithm.

Effect of Social Norm on Consumer Demand: Multiple Constraint Approach

  • Choi, Sungjee;Nam, Inwoo;Kim, Jaehwan
    • Asia Marketing Journal
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    • v.22 no.1
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    • pp.41-60
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    • 2020
  • The goal of the study is to understand the role of social norm in purchase decisions where demand is revealed in the form of multiple-discreteness. Consumers are socially engaged in various activities through the expectation from others in their community. Actions or decisions are likely to reflect this influence. This implicit or explicit social norm is revealed as the rules, regulations, and standards that are understood, shared, endorsed, and expected by group members. When consumers' decisions are in distance from the norm, they come to face discomfort such as shame, guilt, embarrassment, and anxiety. These pressure act as a constraint as opposed to utility in their decision making. In this study, the effect of social norms on consumer demand is captured via multiple constraint model where constraints are not only from budget equation but also from psychological burden induced by the deviation from the norm. The posterior distributions of model parameters were estimated via conjoint study allowing for heterogeneity via hierarchical Bayesian framework. Individual characteristics such as age, gender and work experience are also used as covariates for capturing the observed heterogeneity. The empirical results show the role of social norm as constraint in consumers' utility maximization. The proposed model accounting for social constraint outperforms the standard budget constraint-only model in terms of model fit. It is found that people with longer job experience tend to be more robust and resistant to the deviation from the norm. Incorporating social norm into the utility model allows for another means to disentangle the reason for no-purchase as 'not preferred' and 'not able to buy'.

Investigation of decontamination characteristics of a serial multiple pool scrubber system for consequence mitigation of severe accidents

  • Hyeon Ho Byun;Man-Sung Yim
    • Nuclear Engineering and Technology
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    • v.54 no.12
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    • pp.4585-4600
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    • 2022
  • A pool scrubber is often used as a wet-type design to mitigate the consequence of a severe nuclear accident. While studies indicated higher decontamination performance of a deeper pool, utilizing a very tall pool can be problematic due to potential structural stability and water backflow issues. This study proposes, as an alternative to a single pool system, a pool scrubber system composed of serially connected multiple pools with lower heights. Since large fraction of aerosol removal takes place in the injection region, serially connected pool scrubber system is expected to enhance the overall decontamination capability of a pool scrubber system. To support the analysis of the proposed system's decontamination capability, a new computer model was developed in the study to describe the bubble size dependent effect on aerosol removal including the effect of pool residence time. The accuracy of the new model was examined against experimental data for its validation. The proposed scrubber system composed of serially connected multiple shorter pools is found to have much improved decontamination performance over the current single pool system design.