Compensation In Order Research Articles

Vacuum Circuit Breakers in Flexible AC Transmission Systems

This paper shows two applications for using vacuum circuit breakers (VCBs) in flexible ac transmission systems in the high-voltage (HV) power grid. This is first a mechanically switched reactor, which is series connected to a thyristor-controlled series compensator in order to enhance the inductive working range. Nevertheless, the switching frequency of VCBs is limited by their mechanical properties. In order to achieve a higher switching frequency, more VCBs are switched in parallel to each other. Second, a device is investigated, which consists of mechanically switched capacitors and a mechanically switched reactor. It is connected to a node in the HV system in order to enhance the voltage quality and to avoid a voltage collapse. Since VCBs are mainly available in the medium-voltage range, a transformer is used to connect the mechanically switched device to the HV system. In this paper, it could be shown that the mechanically switched series reactor is able to enhance the damping progress of power oscillations and that the mechanically switched device using VCBs can stabilize the voltage of the node in case of disturbances, such as faults in the power system. Furthermore, the electrical stress on the VCBs has been assessed for different simulation cases with PSCAD.

Non-invasive Transcutaneous pCO2Gas Monitoring System for Arterial Blood Gas Analysis

Monitoring the carbon dioxide concentration in arterial blood is vital for the evaluation and prevention of pulmonary disease. Yet, domestic pure arterial blood carbon dioxide sensor technologies are not being developed, instead all sensors are imported. In this paper, we develop a real time monitoring system for arterial blood partial pressure of carbon dioxide(<TEX>$pCO_2$</TEX>) gas from the wrist by using a carbon micro-heater. The micro-heater was fabricated with a thickness of 0.3 <TEX>${\mu}m$</TEX> in order to collect the carbon dioxide under the skin. The micro-heater has been designed to perform temperature compensation in order to prevent damage to the skin. Two clinical trials of the system were undertaken. As a result, we demonstrated that a portable, transcutaneous carbon dioxide analysis(<TEX>$TcpCO_2$</TEX>) device produced domestically is possible. In addition, this system reduced the analysis time significantly. Carbon films could reduce the unit price of these sensors by replacing the gold film used in foreign models. Also, we developed a real time monitoring system which can be used with optical biosensors for medical diagnostics as well as gas sensors for environmental monitoring.

Design of a CMOS Bandgap Reference with Low Temperature Coefficient and High Power Supply Rejection Performance

A high precision temperature compensated CMOS bandgap reference is presented. The proposed circuit employs current-mode architecture that improves the temperature stability of the output reference voltage as well as the power supply rejection when compared to the conventional voltage-mode bandgap referenc. Using only first order compensation the new architecture can generate an output reference voltage of 550mV with a peak-to-peak variation of 400μV over a wide temperature range from -25 o C to +100 o C which corresponds to a temperature coefficient of 5.8ppm/oC. The output reference voltage exhibits a variation of 2.4mV for supply voltage ranging from 1.6V to 2.0V at typical process corner. A differential cascaded three-stage operational amplifier is included in the bandgap circuit to improve the power supply rejection of the BGR. Simulation result shows that the power supply rejection ratio of the proposed circuit is 79dB from DC up to 1kHz of frequency. The proposed bandgap reference is implemented using UMC 0.18μm CMOS process and it occupies an active layout area of 0.14mm 2 .

Tenure track system in higher education institutions of Pakistan: Prospects and challenges

Tenure track system (TTS) was introduced in higher education institutions of Pakistan in 2002 as part of administrative reforms. The main objectives of the reform were to improve performance of higher education in the country through attracting qualified people and improving performance of academic faculty of higher education institutions particularly the public sector universities of Pakistan. The paper discusses implementation of TTS to find factors that facilitate or impede its implementation in higher education institutions of Pakistan. Triggered by a report entitled, ‘higher education in developing countries – peril and promise’ published by the World Bank and UNESCO in 2000, the government of Pakistan initiated a process of reform in the higher education sector. The report developed as part of the process recommended for making certain revisions in the higher education including the recruitment and selection, compensation and performance management systems in order to make them more efficient and better performance oriented. TTS introduced by the Higher Education Commission of Pakistan (HEC) in the following years draws heavily from the findings of the report. Based on the findings of an empirical study conducted on the subject the paper assesses TTSas an administrative reform and identifies its prospects and challenges to the higher education institutions in Pakistan. Using the Government College University (GCU) as a case in point the paper provides useful suggestions towards smooth implementation of TTS in view of improving performance of higher education and the institutions/universities involved. It also discusses policy implications and offers guidelines towards strengthening the system by removing the weaknesses at an early stage of implementation. Key words: Higher Education Reforms, Tenure Track System, Implementation Assessment, Change Management.

Differentiated Compensation: How California School Districts Use Economic Incentives to Target Teachers

Many districts and schools have trouble recruiting and retaining teachers who have the necessary credentials and skills to meet the needs of their students. This trend is particularly severe in low-income, "high-needs" schools and districts. As such, districts and schools are implementing policies that are intended to reform compensation in order to increase teacher recruitment and retention. Although much of the recent discussion surrounding teacher compensation has centered around districts' use of merit pay, many districts are already using differentiated compensation incentives to target specific kinds of teachers in an attempt to attract and retain not only the highest quality teachers, but also the teachers districts most need to teach in their specific local contexts. Using a self-collected dataset of California school districts from the 2005-2006 and 2008-2009 school years, the frequency with which districts in California use targeted economic incentives and the kinds of districts that are most likely to implement such policies are examined. While many school districts in California have economic incentive policies targeted at teachers with specific skills or credentials, most incentive policies are focused on teachers with rough proxies for "quality." Those that do target teachers in high-need subjects, for the most part, focus on rewarding those certified to teach special education students and English language learners (ELLs)—few are aimed at teachers of other hard-to-staff subjects such as math or science. In addition, there is limited evidence that particularly "hard-to-staff" districts—such as those with high proportions of minority and poor students and those with low academic achievement—are more likely to implement economic incentives that target teachers with specific subject credentials and are less likely to focus their efforts on attracting and retaining "high-quality" teachers.

A note on the optimality of (even more) incomplete strict liability

This paper starts from the premise that liability is incomplete and establishes that firms may nevertheless invest excessively in care. This may justify a (further) reduction in the level of liability from a social standpoint, thereby arguing against seeking to approach full compensation as close as possible. In our framework, firms are liable under product liability, but also invest in care to prevent consumers’ switching to competitors. Affecting the partition of consumers by means of care-taking is not desirable from a social standpoint. Consequently, it may be optimal to reduce liability below a given level of incomplete compensation in order to adjust firms’ care incentives.

A neural network-based direct adaptive fault tolerance flight control for control surface damage

In order to enhance the reliability of flight control systems, a new neural network-based direct adaptive fault tolerance control was proposed for flight control system in the presence of control surface damage. Based on the accuracy approach of neural network, a fault parameter identification models were built to constitute hybrid compensator in order to ensure the strictly positive real of the failure flight control systems in the inner control loop. In the outer loop, a common direct adaptive controller was designed. The scheme was illustrated through simulations using an aircraft. The results show that an aircraft has also good dynamic performance in the control surface damage.

Dosimetric verification of compensated beams using radiographic film

IntroductionExternal photon beam modulation using compensators in order to achieve a desired dose distribution when brachytherapy treatment is followed by external beam radiation is a well-established technique. A compensator modulates the central part of the beam, and the dose beneath the thickest part of the compensator is delivered mostly by scattered, low energy photons. A two-dimensional detector with a good spatial resolution is needed for the verification of those beams. In this work, the influence of different types of detectors on the measured modulated dose distributions was examined.Materials and methodsDosimetric verification was performed using X-Omat V, Eastman Kodak radiographic films at different depths in a solid water phantom. The film measurements were compared with those made by ionization chambers. Photon beams were also modelled using EGSnrc Monte Carlo algorithm to explain the measured results.ResultsMonte Carlo calculated over-response of the film under the thickest part of the compensator was over 15%, which was confirmed by measurements. The magnitude of over-response could be associated with changes in the spectra of photon energy in the beam.ConclusionsThe radiographic film can be used for the dosimetry of compensated high energy photon beams, with limitations in volumes where photon spectra are hardly degraded.

Color Saturation Compensation in iCAM06 for High-Chroma HDR Imaging

An image appearance model called iCAM06 was designed for high dynamic range (HDR) image rendering. The dynamic range of an HDR image needs to be mapped on output devices, which is called tone compression or tone mapping. The iCAM06, the representative HDR rendering algorithm, uses tone compression for image reproduction on the low dynamic range of output devices. However, color saturation reduction occurs during its tone compression process. We propose a saturation correction method using the inverse compensation in order to recover the saturation reduction in the iCAM06. Experimental results show that the proposed method has better performance than the iCAM06 from the viewpoint of saturation accuracy and rendering preference.

Kinematic Calibration and Forecast Error Compensation of a 2-DOF Planar Parallel Manipulator

Due to large workspace, heavy-duty and over-constrained mechanism, a small deformation is caused and the precision of the 2-DOF planar parallel manipulator is affected. The kinematic calibration cannot compensate the end-effector errors caused by the small deformation. This paper presents a method combined step kinematic calibration and linear forecast real-time error compensation in order to enhance the precision of a two degree-of-freedom (DOF) planar parallel manipulator of a hybrid machine tool. In the step kinematic calibration phase of the method, the end-effector errors caused by the errors of major constant geometrical parameters is compensated. The step kinematic calibration is based on the minimal linear combinations (MLCs) of the error parameters. All simple and feasible measurements in practice are given, and identification analysis of the set of the MLCs for each measurement is carried out. According to identification analysis results, both measurement costs and observability are considered, and a step calibration including step measurement, step identification and step error compensation is determined. The linear forecast real-time error compensation is used to compensate the end-effector errors caused by other parameters after the step kinematic calibration. Taking the advantages of the step kinematic calibration and the linear forecast real-time error compensation, a method for improving the precision of the 2-DOF planar parallel manipulator is developed. Experiment results show that the proposed method is robust and effective, so that the position errors are kept to the same order of the measurement noise. The presented method is attractive for the 2-DOF planar parallel manipulator and can be also applied to other parallel manipulators with fewer than six DOFs.

Constrained control of hot air blower system under output delay using globally stable performance-based anti-windup approach

This paper describes the design and implementation of a linear controller with an Anti-Windup Compensator (AWC) for a hot air blower system having output delays, under actuator saturation constraint and noise. Traditional Anti-Windup (AW) schemes for timedelay systems are based on either local stability or global stability with performance restrictions. We modify an existing AWC architecture using a time-delay term in the compensator in order to ensure global stability and performance. It is also shown that the existing Linear Matrix Inequalities (LMIs) based optimization schemes for AWC, which are derived using the decoupled architecture and coprime factorization, can be applied to the modified AWC architecture. This modified delay independent AWC scheme is applied to a hot air blower system and practical results are discussed. This paper aims to support the industrial application of the modified AWC ensuring global stability and performance, by applying it to a hot air blower system under actuator situation and output delay as well as electrical and thermal noises.

A Negligent Blow to Children at Risk: MAK and RK v United Kingdom (European Court of Human Rights)

In MAK and RK v United Kingdom the European Court found that the absence of a common law duty of care owed to parents by doctors falsely suspecting them of their child's abuse violated the European Convention on Human Rights. This appears to be so even where the suspicion is a reasonable and blameless one to make, all things considered. In such circumstances, the court's decision to find that a parents' Convention rights had been unjustifiably infringed, and to order compensation accordingly, is likely to have the effect of frustrating the effective protection of children genuinely at risk of abuse.

측정에러가 있는 적분기 시스템에서의 상태 궤환 제어기 설계 및 분석

In this paper, we propose a fault-tolerant controller for compensating measurement noise of feedback sensor. Because control systems operate via feedback sensor`s signal, the measurement noise in sensor`s signal results in performance degradation or even system failure. Therefore, control systems often demand on compensating measurement noise. Our controller is equipped with a compensator in order to reject or reduce the effect of measurement noise in feedback information. Our proposed method is verified via simulation and experiment for a Ball and Beam system.

Satisfaction of gain and phase margin constraints using proportional controllers

Gain and phase margins (GM and PM) are frequently used as robustness indicators for linear time invariant systems. In many cases, the design problem is reduced to determination of a loop gain to satisfy several design criteria including gain and PM specifications. Therefore finding the set of fixed order compensators that satisfy given gain and PM specifications attracted the attention of a considerable part of the scientific community recently. It is possible to show that it may not be possible to satisfy the required gain and/or PM specifications using only a proportional controller. As a result, finding the limits of the proportional controllers for a given plant (i.e. finding the maximum achievable gain and PMs, MAGM and MAPM) is also important. After providing alternative methods (to those that already exist in the literature) for determining all stabilising proportional controllers that satisfy gain and PM constraints, a new method for calculating MAGM and MAPM using proportional controllers is given in this article. A formulation to calculate maximum gain that results in MAGM is also provided.

Modified acceleration feedback for active vibration control of aerospace structures

An acceleration feedback control method suggested in several past studies is modified toinclude two compensators, one first order and another second order, to separately controlthe closed-loop system stiffness and damping. The second order compensator has adamping ratio that is as low as that of the flexible structure in order to provideperiodic vibration control. The first order compensator is used to provide thenecessary damping, simultaneously. Employing two separate compensators allow us toprovide stiffness and damping control in a dynamically decoupled manner. The newcontroller is readily applicable to a strain-based sensing and actuating approach,such as piezoelectrically controlled systems. Control gains are obtained through astability analysis that is described in detail in the paper. The effectiveness of thecontroller is verified experimentally using a test setup that includes a flexibleplate. The plate includes two small piezoelectric patches that are used as controlactuators. Ten miniature size accelerometers are mounted on the plate for measuringplate vibrations. Two piezoelectric actuators in different positions are used forvibration control of the plate and the results are compared with the condition inwhich only one actuator is used. In addition, the results confirm that the newcontroller is able to effectively control more than one frequency simultaneously.

Experimental Implementation on Vibration Mode Control of a Moving 3-PRR Flexible Parallel Manipulator with Multiple PZT Transducers

This paper presents the experimental implementation of active vibration control applied to a moving 3-PRR parallel manipulator with three flexible links. The active vibration control is implemented using three piezoelectric (PZT) transducer pairs applied to one flexible intermediate link based on modal strain rate feedback (MSRF) control. A real-time active vibration control system is developed using two PCs with LabVIEW Real-Time. Modal analyses are conducted, and the results demonstrate that the vibration modes of the intermediate links are dynamically coupled and the vibration frequency components are complicated and closely spaced. Simplified and efficient modal filters are developed to extract modal coordinates in real time, and a second order compensator is used to filter amplified noises and unmodeled high frequency dynamics. A MSRF controller is then designed using an independent mode space control strategy, and is implemented experimentally with the first mode targeted for control. Experimental results demonstrate that the vibration amplitude of the first vibration mode of the intermediate link is significantly reduced using three PZT control pairs. The experimental results using one PZT control pair and two control pairs are provided to justify the use of three PZT control pairs.

Evaluation of Static Synchronous Compensator in Order to Loading Margin Study in Power System

This paper presents a study of FACTS devices mainly static synchronous compensator (STATCOM) on loading margin study and power stability. Their steady state modeling and effects on power system performance have been studied. Effects of STATCOM on system loadability have been discussed and presented here. Continuation power flow is used to evaluate the effects of this device on system loadability. Eigenvector analysis applied at the maximum loading point is used to rank the most critical voltage buses. After that, it would be possible to optimize location of STATCOM in order to achieve maximum enhancement of system loadability. The models and methodology for placing STATCOM are tested in a 14 bus system. Test system reveals that the incorporation of STATCOM significantly improves Loading Margin and the line power transfer capability of the system and therefore, the stability of the system is increased.

Evaluation of static synchronous compensator in order to loading margin study in power system

This paper presents a study of FACTS devices mainly static synchronous compensator (STATCOM) on loading margin study and power stability. Their steady state modeling and effects on power system performance have been studied. Effects of STATCOM on system loadability have been discussed and presented here. Continuation power flow is used to evaluate the effects of this device on system loadability. Eigenvector analysis applied at the maximum loading point is used to rank the most critical voltage buses. After that, it would be possible to optimize location of STATCOM in order to achieve maximum enhancement of system loadability. The models and methodology for placing STATCOM are tested in a 14 bus system. Test system reveals that the incorporation of STATCOM significantly improves Loading Margin and the line power transfer capability of the system and therefore, the stability of the system is increased. Keywords: Continuation power flow; maximum loading; STATCOM; voltage stability

Victims' Reparations Claims and International Criminal Courts: Incompatible Values?

This article examines the emerging practice on victims' claims for reparation in the context of international criminal proceedings. International criminal courts have followed the model of domestic jurisdictions allowing criminal courts to order compensation by the convicted person to the victim. Yet, remedies for victims in domestic criminal courts function far from optimally. Domestic courts face various problems, relating to technical questions of civil law concerning applicable law, evidence and statute of limitation. These civil law problems often prevent domestic criminal courts from ordering compensation, referring victims to civil courts instead to obtain reparation. The question arises how international criminal courts handle the obstacles inherent in civil law claims that are examined during criminal proceedings.

制御器の状態を考慮した静的アンチワインドアップ補償器の設計(機械力学,計測,自動制御)

In this paper, we propose a design method of a static anti-windup compensator in order to improve tracking performance. A new L_2 gain performance index that includes not only plant state but also controller state is introduced, and a design procedure based on linear matrix inequality is developed. It is demonstrated by the angular control of a belt-drive system that a good tracking performance is attained by tuning the weights on the states of the performance index.