economy and environment through investigating people’s awareness for the potential of the tourism industry. To achieve this goal, we designed a field survey containing both closed survey statements and open-ended questions to identify the rippleeffects from the awareness of local residents. In order to know about the current situation, we introduce the framework of the three aspects of economy, society and environment, and their influences of tourism development. Hart  described that the quality of life should be measured by these three sectors in order to develop a sustainable community. Nishihara et al.  introduced this framework to investigate sustainable tourism development. Because this framework is useful to design an effective field survey, we also used the three sections to list survey statements. To identify the difference of consciousness between different occupations, the survey was targeted at Nepalese respondents working in various occupations, such as the tourism industry and farming. In this research, these respondents were stratified into three categories in terms of industries: the people working in tourism for international tourists, the people working in tourism for domestic tourists, and the people working in other industries, in particular, farming.
In order to reduce the long-term economic impacts caused by disasters and accelerate the economic recovery in the disaster aftermath, this paper uses two scenarios and three models to calculate and analyze the spatial heterogeneity of direct eco- nomic loss and the rippleeffects of indirect economic loss in the streets, villages, and towns of BJ. We used the scenar- ios of direct economic loss to introduce the sectors’ losses caused by the 2008 WCE in BJ, used the rescue scenarios to assess the necessity of improving rescue efforts, adopted the ARIO model to evaluate the indirect economic loss of BJ, and established the SDN model and the IRRE model to assess the direct and indirect economic loss of 321 streets, villages, and towns of BJ. The results indicate that the high value of indirect economic loss is more concentrated in the center of BJ compared with that of direct economic loss. The finance and insurance industry (15) of Chaowai Street in the Chaoyang District suffers the most serious indirect economic loss. During the 6 years after catastrophe occurred (2008– 2014), the average annual GDP growth rate of BJ decreased from 8.55 to 4.91 %. Compared to BJ’s 8 % GDP growth rate target, it is a significant and noticeable economic impact.
17. Shonkoff JP, Garner AS, American Academy of Pediatrics Committee on Psychosocial Aspects of Child and Family Health; Committee on Early Childhood, Adoption, and Dependent Care; and Section on Developmental and Behavioral Pediatrics. The lifelong effects of early childhood adversity and toxic stress.
that the ripple eﬀects between regional house prices may be facilitated by economic activities, such as interregional migration, equity transfer and spatial arbitrage. Meen (1999) was also one of the ﬁrst scholars to provide a general empirical method for studying the ripple eﬀect in the housing context. His method is equivalent to testing the stationarity of the regional to national house price ratios. Using the traditional augmented Dickey-Fuller (ADF) test, however, Meen (1999) was not personally successful in conﬁrming the ripple eﬀect. In response, other scholars later used more advanced stationarity test procedures based on his empirical framework to study the ripple eﬀect. For instance, the threshold and momentum threshold autoregressive test procedures were adopted by Cook (2003), while Holmes and Grimes (2008) combined unit root test and principal component analysis to examine the ripple eﬀect for the UK. Canarella et al. (2012), also studied the house price ripple eﬀect in the US by combining the generalised least squares version of the ADF with non-linear unit root tests and other procedures that control for structure breaks. The Bayesian and panel seemingly unrelated regressions augmented Dickey-Fuller (SURADF) methods for testing unit roots have also been used by a section of the housing literature (e.g. Balcilar et al., 2013; Lee and Chien, 2011; Holmes, 2007). Some researchers recently have advocated using dynamic spatial modelling
staff demand. Additional staff is then added, further diluting experience. This cycle represents a positive feedback loop. The impact of increasing staff on rework is temporary as the new workers gain experience and the rework rippleeffects decrease (Figure 6) Using overtime to improve schedule performance can (after a delay) cause developers to “burnout” due to fatigue from sustained overtime, increasing error fraction and reducing productivity (Figure 6). Pushing developers for more output can cause a “haste makes waste” dynamic which immediately increases errors produced on the project (Figure 6). All of these forms of policy resistance create positive feedback loops, or vicious circles, which can cause a project to spin out of control. 7
The surface floating far above the other two surfaces represents the carry look- ahead data, the surface in between the other two represents the dynamic ripple carry data, and the bottom surface represents the static ripple carry data. From these graphs, not only can it be seen that the carry look-ahead is the fastest design, but the general trend of increasing speed with increasing VDD and temperature can be seen as well.
Induction motors are the most widely used machines in AC drives because of their rugged construction and cost . To control the torque and flux of the induction motor different strategies are available as per the literature. Direct torque control is one of the methods which is used in variable frequency drives for the control of the induction motor. Direct torque control has emerged over the last decade to become one possible alternative to the well-known Vector Control of Induction Machines. In DTC, the stator flux and the torque are directly controlled by selecting the appropriate inverter state. The output of the speed regulator (PI controller) results in generation of the reference torque. However the PI controller cannot result in perfect control if its parameters Kp, Ki are not properly chosen. The undesired torque and flux ripple may occur in conventional direct torque controlled induction motor drive. DTC can improve the system performance at low speeds by continuously tuning the regulator by adjusting the Kp, Ki values. Many artificial intelligence techniques and random search methods have been employed to improve the control parameters.
In this paper, we described that the low pass Butterworth filter are maximally flat as an amplitude response in the passband, and there is no ripple in passband. The transition time is controlled when you increase the filter order otherwise to obtain the accuracy of filter. The Butterworth response is compared to other filters like Che- byshev-I, Chebyshev-II and Elliptic filters perform better response, and finally draw all filter response in the Matlab 7 for filter response comparisons. Finally, the Butterworth filter comparison is very simple and takes low order for accuracy, but we cannot achieve satisfactory results, so here I suggested other methods or even auto- matic low filter techniques available to generate different Low Pass Filter responses that adapt to a task.
in Fig. 13. By knowing the power of output load, the average current of load is determined, so its value is considered as a reference current. The output voltage and input current of the proposed converter are shown in Fig. 14 and Fig. 15, respectively. As indicated in this ﬁgure, by implementing the mentioned switching method for the proposed converter, the input current ripple is low. Also, by comparing the setting time of output voltage of proposed converter with the setting time of hard switching method (see Fig. 9), it is clear that the setting time of the proposed converter is lower.
ABSTRACT: This paper deals with the direct torque control (DTC) of BLDC motor drives by using particle swarm optimization technique. BLDC motors have wide variety of advantages like higher speed ranges, higher efficiency, and better speed versus torque characteristics. Direct torque control (DTC) is one of the efficient methods used in variable frequency drives to control the BLDC motor. DTC offers many advantages like fast torque response, no need of coordinate transformation and less dependence on the rotor parameters. In DTC, the estimated flux magnitude and torque are compared with their reference values. The reference torque is generated from the output of the speed regulator (PI controller).Tuning PI parameters (Kp, Ki) are essential to DTC system to improve the performance of the system at low speeds. In conventional PI controller, the performance of the motor may cause unexpected torque disturbances. Particle swarm optimization (PSO) is proposed to adjust the parameters (Kp, Ki) of the speed controller in order to minimize torque ripple, flux ripple, and stator current distortion.The simulation results of BLDC drive employing conventional PI and PSO based PI controllers is compared and evaluatedunder various load disturbances in the MATLAB/simulink environment.
A nine level inverter consists of a series H-bridge inverter units connected to three phase induction motor. The general function of this multilevel inverter is to synthesize a desired voltage from several dc sources. The AC terminal voltages of each bridge are connected in series. Unlike the diode clamp or flying capacitors inverter, the cascaded inverter does not require any voltage clamping diodes or voltage balancing capacitors .This configuration is useful for constant frequency applications such as active front-end rectifiers, active power filters, and reactive power compensation. In this case, the power supply could also be the voltage regulated dc capacitor. One important characteristic of multilevel converters using voltage escalation is that electric power distribution and switching frequency present advantages for the implementation of these topologies. The Fig.1 shows the multilevel inverter topology. This paper makes an overview to find the various induction motor drive configurations used in industry . The various control strategies used to improve drive efficiency and various inverter used to control the motor speed, reduce torque ripple, current ripple and reduce harmonics . Also different topologies and control strategies are useful for different situations. One of the very efficiently used control strategies is the sinusoidal PWM control which can be implemented.
The carry look ahead adder represents the most widely used design for high-speed adders in modern Computers. The advantage of using a look-ahead design over a ripple carry adder is that the Look-ahead is faster in computing the solution. The carry-in values in a carry look-ahead design are calculated independent of each other through a series of logic circuits. Carry look ahead depends on two things:
Characteristic of Power quality has been with us since the inception of the electrical Power system. However, the topic of power quality has attracted particular attention in recent years due to the increase of electronically controlled. Power quality problems caused disruptions to electrical or electronic equipment and the resulting consequences are very expensive. Ripple techniques will be studied in this paper for analyzing power quality monitoring. In the case study based on the measurement of the site of the Asian Institute of Technology (AIT) and it was examined using the proposed ripple technique.
1. Introduction. Class-D ampliﬁers are a technologically signiﬁcant application of switching electronics. An audio signal (of relatively low frequency) is converted by a class-D ampliﬁer to a high-frequency rectangular wave. The latter wave generally has a ﬁxed frequency but a duty cycle that is modulated slowly according to the audio signal (the duty cycle being the proportion of time the output is “on”). The conversion from audio signal to rectangular wave is called pulse-width modulation (PWM) [3, 8]. The modulation is carried out with the intention that the low-frequency content of the modulated rectangular wave should faithfully reproduce the original audio signal. In practice, however, there are many sources of potential distortion in the out- put. One of particular signiﬁcance follows from the fact that the output rectangular wave switches between the voltages at the power supply rails, and hence any low- frequency ripple in the power supply may become audible in the output. To mitigate such eﬀects, the class-D ampliﬁer generally includes some form of negative feedback. Unfortunately, nonlinearities in the PWM process, coupled to the negative feedback, generate unwanted additional audio components in the output. It is the goal of the ampliﬁer designer to reduce such distortion, and over the years many techniques have been proposed and adopted to reduce output distortion in class-D ampliﬁers [2, 4, 15]. Recently, the technique of ripple compensation [12, 14] (henceforth RC) has been introduced and found to dramatically reduce audio distortion in class-D ampliﬁers. This paper presents the ﬁrst detailed mathematical analysis of RC, which enables us to quantify its notable eﬀectiveness in suppressing nonlinearities in the output. Our analysis is presented for arguably the simplest possible ampliﬁer design, to clarify
The main intention of this work is to design a12T GDI based full adder and to compare the 28T based ripple carry adder and 12T based ripple carry adder. The purpose of this design is, on using the less transistors the delay and power gets reduced when compared between 12T and 28T ripple carry adders. Low power adders having the capability of reducing the power , delay and layout area. A circuit with cascaded N-bit full adder called ripple carry adder. The rippling of carry bit takes place in the ripple carry adder. It is so simple circuit hence it allows a fast design time. The first least significant adder in the ripple carry will be always a half adder.
with feedback linearization and with deadbeat controller. As shown, the response (dashed line) is able to track and follows the reference signal (soled line) after small finite time with steady state error equal zero. This validates the design approach and shows that ripple-free deadbeat control was achieved on a nonlinear unstable system such as the magnetic ball levitation.