Search

The detailed description about the OMIS (One Machine-Infinite Bus) and the SLIS(Single Load -Infinite Bus)will be done in this paper and the detailed introduction of these two concepts(the coherent generators and the coherent buses) and their aggregation. Based on the new OMIS model, the new methods of identifying the coherent generators and aggregating the coherent generators will be advanced. Based on the coherent generators, the new algorithm for the reserving coefficient of the steady angular stability will comes into being. Based on the new SLIS model, the new methods of identifying the coherent buses and aggregating the coherent buses will be put forward. Based on the coherent buses, the new algorithm for the reserving coefficient of the steady voltage stability will be brought about. A real example is used to validate the idea in this paper. A discussion on the angular references between the online data and the offline data will be done when the phases from the WAMS are used. The steady stability of two generators model will be acquired.

In this study, the dynamic stability of plate with the active-damping layer under a thrust is investigated. The structure is actively damped by piezoelectric layers, and adopted a control algorithm for vibration suppression. Thin piezoelectric layers are assumed to be embedded on the top and the bottom surfaces of the structure. The top and the bottom layers are taken as the actuator and the sensor, respectively. The structure model is based on the first-order shear deformation plate theory, and the finite element method is applied in the numerical analysis. In addition, the method of multiple scales is adopted to analyze the parametrically excited system. This analysis is specifically focused on the mutual interaction of the thrust and the piezoelectric active-damping layer for the vibration suppression. In this paper, the effects of the active-damping layer with piezoelectric sensors/actuators are discussed in detail.

Optimal pressure regulation to reduce water losses in water distribution systems (WDSs) becomes an important concern due to the increasing water demand and the threat of drought in many areas of the world. The leakage amount in a WDS depends heavily on its operating pressure and thus can be minimized by implementing optimal pressure strategies through pressure reducing valves (PRVs). To achieve this, a model-based optimization is necessary, where an accurate model of the PRVs is required. The PRV models having been used until now for pressure regulations are two-mode models which cannot circumstantiate many situations occurring in WDSs. In this paper, we extend the existing model by a three-mode one for PRVs which is able to describe the required circumstances of pressure regulations in WDSs. The non-smoothness of this model is smoothed by an approximation approach, thus allowing the formulation and solution of a continuous nonlinear optimization problem for optimal pressure regulation. Two benchmark WDSs are used to verify our approach and it can be shown from the results that our PRV model outperforms the existing models in terms of the quality and accuracy of the optimal solutions.

This paper presents a new transistor self-oscillating inverter suitable for high efficiency switch mode power supplies, which can operate directly from high voltages and is free from output transformer saturation problems due to transistor characteristic mismatch. It uses a half-bridge power circuit, consisting of two transistors in one limb and two capacitors in the other. Amongst several advantages of this configuration, the switching transistors need to withstand a minimum voltage equal to the dc supply only and not higher as in conventional circuits, while using only two transistors.

This paper presents a kind of design scheme about radar echo wave signal processing system based on digital signal processor (TMS320C6416) and FPGA (EP2C8Q). This scheme is used to timely monitor radar echo data and then calculates it. Distance of target items can be obtained by this method. Take advantage of flexibility and easy-processing complicated data of FPGA and DSP, we promote property of this system to a large extent

This paper presents the results of cement-based mortars characterizations that were taken from rendered layers of military bunkers in the Rupnik Line. The Rupnik Line was conceived as a part of the fortified defence system protecting the Rapallo Border between the Kingdom of Italy and the Kingdom of Yugoslavia, established in 1920. The bunkers were built between 1938 and 1941, and the renders of various compositions were applied as a camouflage layer that merged the bunkers with the environment. Results of petrographic examination and microstructural and chemical analysis of the samples confirmed that locally available crushed dolomite or limestone sands were used as an aggregate in the mortars. As binders, pure Portland cement or a mixture of cement and ground granulated blast furnace slag were used. The selection of the aggregate and binder type in a particular mortar was based on the colour of the artificial stone produced. All samples with the dolomite aggregate show the presence of alkali-aggregate reactions, dedolomitization of the grains and secondary calcite formation in the cement binder, along with the Mg-Al, Mg-Si and Mg-Al-Si phase formations. In mortar compositions with a high Portland cement content, the presence of delayed ettringite formation was also confirmed.

The refrigerant after the expansion valve interchanges the heat at the evaporator. At this moment, the state of gas and liquid becomes two-phase flow and causes irregular noise. In order to avoid the noise, the two-phase flow pattern should be predicted. In this paper, the procedure to predict the two-phase flow patterns such as churn flow and annular flow was suggested using the CFD software. The experiments using refrigerant-supplying equipment was carried out and the noise levels according to the flow pattern were measured. The flow patterns predicted by this procedure showed good agreement with those by experiments. The churn flow is noisier than annular flow pattern.

In an ESP (English for Specific Purposes) and ELP (English for Legal Purposes) perspective, this paper studies the construction of professional cultural competence through the cultural substrata woven into the narrative of specialised popular fiction, or FASP.After a brief overview of the theoretical framework retained and the functions of a coroner in England and Wales, the discussion focuses on a coronial FASP, M. R. Hall’s The Coroner (2009), to analyse three cultural strands which relate meaningfully to ELP learner objectives: culture specific to the Coroner’s Office, broader social commentary with regard to issues concerning the legal community as a whole and, finally, locus-related societal and national cultures.The paper concludes by addressing reservations expressed regarding such randomly acquired knowledge by highlighting the advantages of a heuristic and semasiological approach in exploring both target and source culture. Dans le cadre de la didactique des langues et cultures spécialisées du droit, cet article porte sur la construction d’une compétence de culture professionnelle à travers les substrats culturels tissés dans la fibre narrative de la fiction populaire spécialisée, la FASP.Après une brève présentation du cadrage théorique retenu, du professionnel de droit qu’est le coroner au Royaume Uni et de la FASP juridique qui constitue l’objet d’étude, The Coroner (2009) de M. R. Hall, l’analyse dégage trois domaines culturels en lien avec les objectifs de l’apprentissage : la culture spécifique à l’environnement spécialisé du professionnel qu’est le coroner, le commentaire social enchâssé dans le récit qui se rapporte à la communauté juridique dans son ensemble et, finalement, les cultures relatives aux lieux qui servent d’ancrage géographique au récit fictif.Pour conclure, l’auteur répond aux réserves souvent exprimées concernant la nature fragmentaire des connaissances acquises par l’intermédiaire de la FASP en mettant en avant les avantages d’une approche heuristique et sémasiologique dans l’exploration des cultures cible et source.

This paper presents a collaboratively adaptive vibration monitoring system that captures high-fidelity structural vibration signals induced by pedestrians. These signals can be used for various human activities’ monitoring by inferring information about the impact sources, such as pedestrian footsteps, door opening and closing, and dragging objects. Such applications often require high-fidelity (high resolution and low distortion) signals. Traditionally, expensive high resolution and high dynamic range sensors are adopted to ensure sufficient resolution. However, for sensing systems that use low-cost sensing devices, the resolution and dynamic range are often limited; hence this type of sensing methods is not well explored ubiquitously. We propose a low-cost sensing system that utilizes (1) a heuristic model of the investigating excitations and (2) shared information through networked devices to adapt hardware configurations and obtain high-fidelity structural vibration signals. To further explain the system, we use indoor pedestrian footstep sensing through ambient structural vibration as an example to demonstrate the system performance. We evaluate the application with three metrics that measure the signal quality from different aspects: the sufficient resolution rate to present signal resolution improvement without clipping, the clipping rate to measure the distortion of the footstep signal, and the signal magnitude to quantify the detailed resolution of the detected footstep signal. In experiments conducted in a school building, our system demonstrated up to 2× increase on the sufficient resolution rate and 2× less error rate when used to locate the pedestrians as they walk along the hallway, compared to a fixed sensing setting.

As the development of autonomous vehicles rapidly advances, the use of convoying/platooning becomes a more widely explored technology option for saving fuel and increasing the efficiency of traffic. In cooperative adaptive cruise control (CACC), the vehicles in a convoy follow each other under adaptive cruise control (ACC) that is augmented by the sharing of preceding vehicle acceleration through the vehicle to vehicle communication in a feedforward control path. In general, the desired velocity optimization for vehicles in the convoy is based on fuel economy optimization, rather than driveability. This paper is a preliminary study on the impact of the desired velocity profile on the driveability characteristics of a convoy of vehicles and the controller gain impact on the driveability. A simple low-level longitudinal model of the vehicle has been used along with a PD type cruise controller and a generic spacing policy for ACC/CACC. The acceleration of the previous vehicle is available to the next vehicle as input, and the simulations are performed as Cooperative Adaptive Cruise Control of a convoy of vehicles. Individual vehicle acceleration profiles have been analyzed for driveability for two different velocity profiles that are followed in a stretch of 720 m between stop signs. The controller gains have been re-tuned based on the parameter space robust control PID approach for driveability and compared with the original gains. The US06 SFTP drive cycle has also been used for the comparison of the two different controller gain sets.

This is the second of two manuscripts which employ finite element analysis and optimization algorithms to design optimal fixtures for drilling through deformable workpieces. Part I has addressed the problem formulation, suggesting five different objective functions that capture different geometric characteristics of the machined surface. The performance of the five obtained fixture layouts under different drilling conditions is studied in this paper. The drilling studies include single, sequential, and simultaneous (gang) drilling. These studies demonstrate the known fact that more frequent setups and longer machining time periods result in higher workpiece accuracies. The simulations also suggest that the proposed optimal fixturing model developed in this study can be used to command greater control over the drilling process, resulting in elevated drilling quality. The numerical value of the latter is captured by the objective function values. The computer simulations further identify optimal fixturing layouts that can be implemented in an industrial environment.

In this paper, an overview of the field of wireless powering is presented with an emphasis on low-power applications. Several rectenna elements and arrays are discussed in more detail: (1) a 10-GHz array for powering sensors in aircraft wings; (2) a single antenna in the 2.4-GHz ISM band for low-power assisted-living sensors; and (3) a broadband array for power harvesting in the 2-18GHz frequency range.

A closed-form displacement response of track subjected to loads moving at variable speeds is proposed in this paper. The structure of the track is modeled as a Timoshenko beam of infinite length that is periodically supported by double-layer spring-damping elements. The frequency-domain displacement response of the track is simplified into the mathematical form of a summation rather than an integral. The transfer function for the track is expressed in the form of a transfer matrix. Various kinds of moving loads, such as single and series moving forces, masses and double-layer mass systems, are considered in calculations. For the verification of the theory, the displacement response of a simply supported beam subjected to masses moving at variable speeds is calculated and compared with reports in the literature on the same case. The obtained results indicate that the influence of the loads moving at variable speeds on the displacement response of the track cannot be ignored, and the displacement response of the track increases slightly with acceleration of the moving loads. Also, larger oscillations are generated by the interaction of the moving mass and the track.

Combustion turbines and combined cycles have become a dominant mode of new capacity addition in most parts of the world. However, to maximize the benefits of a combined cycle, it must be designed to take into account site-specific technical, economic, and environmental considerations. This paper outlines the important design considerations that must be addressed in the early stages of a project's development.

Due to the low cardinality of optical orthogonal codes (OOCs) with a correlation value of 1, the capability of an internal channel-coding scheme cannot be applied effectively for an increasing number of simultaneous users in a typical fiber-optic code division multiple-access (FO-CDMA) system. In this paper, we consider applying the internal channel-coding scheme to the framed time-hopping (FTH) FO-CDMA system. Due to the extremely high cardinality of the spreading sequence in FTH FO-CDMA, the technique highlights the ability of the internal channel-coding scheme to increase the effective number of users in an FO-CDMA system. For the FTH FO-CDMA system, we only consider a Poisson noise-limited channel and do not take into account the physical fiber-optic channel impairments. Our simulation and analytical results show that, due to the large cardinality of spreading codes, the capability of the internal channel-coding technique to increase the maximum number of simultaneous users becomes more obvious in the FTH FO-CDMA system.

This paper investigates the control and safety of a series of maglev trains moving on multi-span simply supported bridges with the foundation settlements. To control the dynamic response of the maglev trains, a PI (proportional-integral) controller with constant tuning gains is applied. The finite element results indicate that the influences of the rail irregularities are obvious. However, the allowable vertical settlement and the Y-deflection of the bridge, which is caused by the X-rotation can be significantly improved when the lateral electromagnetic force is enlarged. Keywords-Maglev train; PI control, Rail irregularity; Finite element method; Foundation settlement; Newmark method

An attempt is here made to survey the state of published knowledge of a branch of electrical engineering that has recently come into prominence and to present an introduction to it in general terms within a range sufficient to explain the development of what in effect is a new technique and its relation to other branches of electrical engineering. The first part of the paper describes the salient properties of electromagnetic waves in hollow metal tubes and reveals the great extent to which the theory of the subject had its origin in the researches of Lord Rayleigh and other investigators who, during the closing years of the last century, worked in Great Britain. It also indicates to how great an extent the development of the theory and its practical application are due to researches carried out during recent years mainly, in the United States. The second part of the paper gives a systematic account of the development of elementary equipment appropriate to hollow tube transmission, with analogies from acoustics, telephony, and radio engineering. The third part describes phenomena observed at the open ends of guides?flared or unflared?and exhibits the efficiency of these devices as radiators of energy into free space. The prospective field of application of guides embraces systems of communication operating over any distance, and providing telephone and television channels in numbers vastly exceeding those of any system of established type. When flared into horns, guides may serve in systems for broadcasting of music or television, for blind landing of aeroplanes, for detecting, locating and man?uvring of ships, and for other purposes for which at present radiators and receivers of conventional type are used. Although the usefulness of such systems may thereby be enhanced or extended in range, their mode of operation is well known and hence their description is beyond the scope of this paper. The full extent of the field of application of guides will ultimately be governed by costs and must, for the present, remain a matter of conjecture; but, judged from the course the development has taken during recent years, conjecture suggests that the field will be large and attractive.

The workshop will be conducted primarily through discussion by the participants. The papers have opened up a wide number of issues that have no easy solution and where, most likely, the solutions will vary from case to case. The discussion portion of the workshop will be broad ranging over the topics we have introduced here.

The concept of multi-constrained analysis of the cutting process is presented for the first time in the paper. The paper adopts a method to solve an important problem which is how to judge the influence of constrains during the cutting process. The research results are applied for HSS drills for cutting stainless steel. On the basis of the multi-constrained analysis combined with methods of simulations and standard experiments, the optimum methods are provided for structure, coating and cutting parameters of cutting tools. For geometric structure of tools, optimization is to increase thickness of cutting and rake angle. Coating optimization strategy is choosing high temperature hardness and low thermal conductivity coating. Optimization of cutting parameter is to adjust feed fate, then select proper cutting speed. The conclusion of paper is helpful for the cutting optimization.

In this paper we propose and analyze a novel, computationally inexpensive packet-error model for infrastructure- to-vehicle (I2V) communications. Based on real-world measurements using IEEE 802.11p devices, the proposed model incorporates the physical layer characteristics and propagation effects in an authentic highway environment with real vehicular traffic. With only a small set of parameters, the model allows to simulate time series of packet error events with a Hidden Markov Model (HMM). We propose this packet error model for the simulation of vehicular connectivity in the context of intelligent transport systems.

This paper focuses on energy cost and consumption in the pasteurised milk sector of the dairy industry which accounts for over 90 percent of the UK milk market. Although the industry is not considered to be energy intensive, it has been shown that there is a significant potential for savings, typically 2.2 million GJ/annum or £10.5 million/annum. This paper aims to show how the pasteurised milk sector can achieve these potential savings, using as its example a recent study of a liquid milk dairy in South Wales. The implementation of Monitoring and Targeting methods for energy management, combined heat and power (CHP) generation and third party energy management are introduced, since these are considered to be novel solutions for this sector of industry.

Northrop Grumman Aerospace System has been developing High Power Lasers for the past 30 years. Area of concern with these high power lasers has always been laser safety. In recent years, NGAS has been successful in developing the megawatt chemical laser such as the Airborne Laser, and kilowatt class solid state laser such as the Joint High Power Solid-State Laser. We have not experienced any significant personnel injury, which we attribute to the lessons learned and the implementation of these safety lessons in these various projects. These various high power lasers that NGAS are developing involve the emission of laser beams into the air, land, water, and the laboratory. This paper will describe the various administrative and engineering measures we have implemented which allow us to operate the lasers safely in these various environments.Northrop Grumman Aerospace System has been developing High Power Lasers for the past 30 years. Area of concern with these high power lasers has always been laser safety. In recent years, NGAS has been successful in developing the megawatt chemical laser such as the Airborne Laser, and kilowatt class solid state laser such as the Joint High Power Solid-State Laser. We have not experienced any significant personnel injury, which we attribute to the lessons learned and the implementation of these safety lessons in these various projects. These various high power lasers that NGAS are developing involve the emission of laser beams into the air, land, water, and the laboratory. This paper will describe the various administrative and engineering measures we have implemented which allow us to operate the lasers safely in these various environments.

In this paper, we have considered Over Design (OD) and Under Design (UD) as two basic forms of negative variability construction that lead to both functional incompleteness and unexpected software quality degradation during design time and run time. To make our approach economically practical to the quality assurance at the whole life cycle of software production process, we aim to ensure that OD and UD are minimized in terms of values under economical goals. These requirements are concretized with the functionality implementation and the quality management of a quality lifecycle.

The design of an elevator system heavily relies on the calculation of the round-trip time under up-peak (incoming) traffic conditions. The round-trip time can either be calculated analytically or by the use of Monte Carlo simulation. However, the calculation of the round-trip time is only part of the design methodology. This paper does not discuss the round-trip time calculation methodology as this has been addressed in detail elsewhere. This paper presents a step-by-step automated design methodology which gives the optimum number of elevators in very specific, constrained arrival situations. A range of situations can be considered and a judgement can be made as to what is the best cost–performance tradeoff. It uses the round trip value calculated by the use of other tools to automatically arrive at an optimal elevator design for a building. It employs rules and graphical methods. The methodology starts from the user requirements in the form of three parameters: the target interval; the expected passenger arrival rate (AR%) which is the passenger arrival in the busiest 5 min expressed as a percentage of the building population; and the total building population. Using these requirements, the expected number of passengers boarding an elevator car is calculated. Then, the round-trip time is calculated (using other tools) and the optimum number of elevators is calculated. Further iterations are carried out to refine the actual number of passengers boarding the elevator and the actual achieved target. The optimal car capacity is then calculated based on the final expected passengers boarding the car. The HARint plane is presented as a graphical tool that allows the designer to visualise the solution. Three different rated speeds are suggested and used in order to explore the possibility of reducing the number of elevator cars. Moreover, the average passenger travel time is used to indicate the need for zoning of buildings. Practical application: This paper has an important application in allowing the designer to arrive at the optimum design for the elevator system using a clearly defined methodology. This ensures that the number of elevators, their speed and their capacity are optimised, thus ensuring that the cost of the elevator system and the space it occupies within the building are minimised. The method also employs a graphical method (the HARint) in order to allow the designer to visualise the optimality and the feasibility of the different design options.

The aim of this paper comprises of investigating the viability of using an available indigenous blade as horizontal axis micro wind turbine blade and further improvement of this particular blade performance through design modification and CFD simulation. The focus was to use this blade in the urban areas of Bangladesh where the air speed is not usually high enough to harness wind energy with a micro wind turbine efficaciously. Though it requires a minimum wind speed of around 4.2 m/s to start self-rotation of this available blade without the help of external aid, the optimized design would demand a less air speed as the torque would be increased and this might be successfully used in roadside or housetop applications. Experimental and numerical analyses were conducted with the blade and the design modification and optimization were done with the help of CFD analysis. The experimental and numerical plots showed excellent similitude in qualitative manner. We went through with the optimization of blade design

ABSTRACT This paper discusses methods for calculating wind and current-induced steady loads on moored vessels. An analysis of existing wind tunnel data was used to develop anew, generally-applicable calculation method for wind loads that accounts for individual vessel characteristics and the natural wind gradient. It is also shown that the accuracy of state-of-the-art methods for calculating current-induced loads is undefinable, given the large scatter among the methods and the absence of validation data. Results are presented from the first known full-scale current loads test. INTRODUCTION A wide range of mooring expertise and technology is required by the U. S. Navy to properly support and execute its missions. The Naval Civil Engineering Laboratory (NCEL) under Naval Facilities Engineering Command (NAVFAC) sponsorship, is contributing to this technology base by developing and validating general purpose mooring analysis computer models. Experience at NCEL using these computer models has generated questions regarding the accuracy of existing methods for estimating steady wind-, wave- and current-induced forces and yaw moments on moored vessels. This article is an overview of NCEL's continuing efforts to improve the state-of-the-art in estimating both wind- and current induced steady loads on moored vessels. These efforts have also served to establish the relative accuracy of existing calculation methods, and have provided examples of the sensitivity of mooring simulations to these steady loads. Wave-induced (drift) steady loads are not considered in this overview, nor are "a typical" vessels such as submarines, catamarans or semi-submersibles. The coordinate system used in this report is illustrated in Figure 1. The excitation is decomposed into a longitudinal force component (X) parallel to the keel, a lateral force component (Y) perpendicular to the keel, and a yaw moment component (N) about the center of gravity. These loads are referenced to the local incident angle (8) between the excitation and the keel of the vessel. NCEL's first mooring simulation using the recently developed mooring models is described in Reference 1. Three different sources of current- and wind induced loads (A, B and C) were used in three different simulations of a 70 KDWT tanker moored by a single hawser to a mooring buoy with four catenary legs. The static and dynamic tensions are summarized in Table 1. The differences among the static tensions demonstrated both the inconsistencies in the state-of-the-art calculation methods, and the sensitivity of the static equilibrium to these loads. The importance of accurately estimating these steady loads was further reinforced by the dynamic tensions comparison. In both the model test and the simulation, the dynamic loads only slightly increased the static tensions. Considering that this mooring system was excited by 12 foot waves, this example demonstrated that dynamic effects are not necessarily more important that the static loads. It was therefore concluded that a thorough investigation of steady loads on moored vessels was needed to have confidence in the simulations.

A laboratory axle efficiency test using a torque sweep method has been developed. Vehicle test limitations, previous axle efficiency tests and origin of current test are discussed. Test development, equipment and importance of technique are presented. Correlation with vehicle tests is shown and usefulness of data for evaluating lubricant and axle design changes is discussed. An evaluation of test results shows that the torque sweep method has the capability of identifying changes that may not show with vehicle tests.

For tight oil reservoirs, because of ultra-low permeability, the radial flow is difficult to be obtained in pressure build-up testing which results in multi-solution of flow model and interpretation results. How to determine the right model and identify the right interpretation result are the key questions. This paper presents a well test interpretation methodology based on time and space scales to increase accuracy of well-test interpretation results. Two steps are performed to determine reasonable flow model and interpretation results based on time and space scales. For the time scales, the history of well testing data for a single well are interpreted and the interpretation results are compared first. Then for space scales, the well test data in space for multi-wells are analyzed. At this stage, the interpretation results of adjacent wells are compared. The reservoir geological data and the production history are used as a reference to appraise the well test interpretation results. After these two steps, the reasonable interpretation model and interpretation results can be determined. Two cases selected from Changqing oilfields whose permeabilities are almost under 0.5mD and fluid flow rates are very low are analyzed and the great application effect is attained. This methodology is applied in Changqing oilfields extensively and is proved to be a great methodology in ultra-low permeability oil reservoirs. It can be expanded to other unconventional reservoirs, such as tight gas, shale gas and so on. The innovation is that this paper derives a well testing analysis methodology to determine right model and identify the right interpretation result based on time and space scales. It can decrease the errors which are caused by multi-solution of flow model and many interpretation results.

In sub-wavelength lithography, light field Alt-PSM (Alternating Phase Shifting Mask) is an essential technology for poly layer printability. In a standard cell based design, the problem of obtaining Alt-PSM compliance for an individual cell layout has been solved well [3]. However, placing Alt-PSM compliant cells together can not guarantee Alt-PSM compliance of the entire chip/block layout due to phase interactions among adjacent cells. A simple solution to this Alt-PSM composability problem is to wrap blank area around each cell, which is very inefficient on chip area usage. In this paper, we formulate the composability problem as a graph model and propose a polynomial time optimal algorithm to achieve Alt-PSM composability with the least impact on cell layout.

The question of the use of tires and tracks on agricultural prime movers is again surfacing. The four-wheel drive market is growing fast, particularly in areas where crawlers have been popular. The relative performance characteristics of tires and tracks are compared in agricultural soil conditions. Performance analysis shows that a four-wheel drive tractor should have a 22 percent higher productivity than a similar weighted track layer in a firm soil. This is due to the higher axle power of the four-wheel drive tractor. A track layer should outproduce a four-wheel drive of equal axle power (with proper weight-to-power) by 12 percent. A four-wheel drive tractor had a 36-50 percent higher productivity than a similar weighted track layer in sugarcane conditions for several tillage operations. For similar weighted tractors, owning and operating costs per hectare for a four-wheel drive tractor were 33 percent less than that for a track layer. No significant differences in soil compaction between crawler and four-wheel drive tractors were found in field experiments. There was no significant compaction below the tillage zone for both tractors. Theoretical predictions agreed well with field experiments.

More than two third share of electricity come from coal fired power plants in India. Coal fired power plants are the largest source of anthropogenic CO2 emissions per unit of electricity generation among all fossil fuel based power plants. There has been climate change and global warming globally due to increasing anthropogenic emission of greenhouse gas (GHG) into the atmosphere. This paper examines life cycle GHG emission such as CH4, CO2 and N2O of a National Thermal Power Corporation (NTPC) Limited power plant using life cycle approach. The various stages involved in the assessment of life cycle GHG emissions in the present study include coal mining, transportation of coal to the power plant and coal combustion for electricity generation. The results show that direct CO2 emission from coal combustion is about 890 g CO2-e/kWh, whereas life cycle GHG emissions amount to 929.1 g CO2-e/kWh. Indirect GHG emissions add up to 4.2% of total emissions. Coal mine methane leakage into atmosphere in India is low since more than 90% of the coal mining is surface mining.

This paper presents an in-wheel motor fault diagnosis and fault-tolerant control method for four-wheel independently actuated (4WIA) electric vehicles. The 4WIA electric vehicle is one of the promising architectures for electric vehicles. While such a vehicle architecture greatly increases the flexibility for vehicle control, it also elevates the requirements on system reliability, safety, and fault tolerance due to the increased number of actuators. A fault diagnosis approach for finding the faulty in-wheel motor/motor driver pair is developed. The proposed diagnosis approach does not need an accurate knowledge on tire-road friction coefficient (TRFC) and is robust to tire force modeling inaccuracies. Based on the in-wheel motor/motor driver fault diagnosis mechanism, a control-allocation based vehicle fault-tolerant control system is designed to accommodate the in-wheel motor/motor driver fault by automatically allocating the control effort among other healthy wheels. Simulations using a high-fidelity, CarSim®, full-vehicle model show the effectiveness of the proposed in-wheel motor/motor driver fault diagnosis and fault-tolerant control approaches.

The use of energy harvesting wireless sensor network (EH-WSN) is a rising wireless communication technology with a wide range of applications such as environment monitoring. Maximizing the number of samples collected by the sink from sensors is a key approach in order to minimize uncertainties for those applications. The considered system in this paper consists of an uplink scenario with EH sensors communicating with a non EH sink, equipped with multiple antennas, receiving data forwarded by the sensors. Using a zero-forcing (ZF) receiver, the data collector (i.e., sink) selects the largest possible set of transmitting sensor nodes to maximize the received quantity of information, while satisfying their signal-to-noise ratio quality of service (QoS) constraints. This paper presents efficient and simple EH node selection algorithms in EH-WSNs in order to maximize the number of selected sensors. The problem is formulated as an integer non linear program that can be optimally solved using an exhaustive search. Due to the prohibitive complexity of such a brute force approach, two low complexity and efficient heuristic algorithms are proposed to perform node selection decisions. Simulation results show the performance of the proposed algorithms and illustrate their adaptability and efficiency in the energy harvesting context.

Automobile final assembly operators must be highly skilled to succeed in a low automation environment where multiple variants must be assembled in quick succession. This paper presents formal user studies conducted at OPEL and VOLVO Group to identify assembly training needs and a subset of requirements; and to explore potential features of a hypothetical game-based virtual training system. Stakeholder analysis, timeline analysis, link analysis, Hierarchical Task Analysis and thematic content analysis were used to analyse the results of interviews with various stakeholders (17 and 28 participants at OPEL and VOLVO, respectively). The results show that there is a strong case for the implementation of virtual training for assembly tasks. However, it was also revealed that stakeholders would prefer to use a virtual training to complement, rather than replace, training on pre-series vehicles.

The paper deals with the numerical calculation of the turbulent flow around double ship hulls, with particular regard to the stern region and the wake. A new coordinate system has been developed for the application of the SIMPLE algorithm of Patankar and Spalding, 1972, applied for external flows. Comparison of the calculated results is made with the measured values for an SSPA Liner model and HSVA Tanker model.

This paper proposes a complete definition of the plane strain problem. It consists of five subtypes: the classical one and four subtypes of the generalized plane strain problem. Among them the axial strain is a compatible condition. Following that definition, for problems which are not more complex than that, the axial load as well as axial strain are linear functions of x, y, and the problems can be solved as a plane strain problem. Their solutions are found by simply superposing the solutions of three of the fundamental equations. According to the fourth subtype of the generalized plane strain problem mentioned, the solutions of a hollow inclusion adhered inside a round hole in an infinite object are given, by which the six stress components of virgin stresses in a rock mass stress measurement using CSIR or CSIRO triaxial probes can be fixed. Comparing the calculated results by the method proposed in this paper with the existing methods, utilizing the data of some authors, it is noticed that the axial stress component calculated by the former method is reduced and that the principal stresses and their directions are altered, which may directly explain the discovery by some authors that the axial stress analyzed by the existing methods tends to a higher value.

Fast and precise spectrum opportunity (SOP) exploration is a fundamental and vital procedure for dynamic spectrum management. In this paper, the temporal rather than geographical feature of spectrum database is investigated. The spectrum prediction is formulated and taken as a function of spectrum database. Furthermore, spectrum sensing is also a choice for SOP exploration to cope with the inefficiency of the solely spectrum database approach on freshness of the information and the precise of the prediction. On that consideration, a joint SOP exploration (JSE) scheme is proposed which determines SOP based on joint spectrum sensing and the spectrum prediction enabled spectrum database. The advantages of spectrum database, spectrum prediction and spectrum sensing can be taken jointly to ascertain SOP. Extensive simulation results demonstrate that the proposed scheme can accommodate to diverse scenarios with different sensing ability of SUs and prediction ability of spectrum database, while the advantages of existing SOP exploration approaches can be jointly taken.

Purpose – The purpose of this paper is to provide a decision-making tool on where to send mining parcels extracted in such a way as to minimize losses arising from mis-classification. The problem is complicated because actual values of mining parcels cannot be known and the decision is made on the basis of the estimation/simulations of the parcels generated from sparse data. Design/methodology/approach – The loss minimization associated with mis-classification is formulated as a non-linear optimization problem and solved by successive mixed integer programming. By assigning reasonable values to some variables making problem non-linear, the problem is converted to a mixed integer programming (MIP) and is solved by a standard MIP optimization engine. Findings – A case study was conducted to see the performance of the proposed approach on a deposit with gold and silver variables. The proposed approach was also compared with conventional grade control approaches. The results showed that the approach proposed could be used for solving grade quality control problem. Practical implications – Grade quality control problem is well-known problem and there is no effective solution approach. This paper proposes to solve the problem through standard operation research software. As such, mine planner and engineers have a means to deal with grade quality problem in mining operations. Originality/value – The paper formulates multi-variable grade quality control problem as an optimization problem on the contrary to previous one-shot approaches. This can increase profit and operation efficiency. The research also use target grades rather than cut-off grade posing problems in mining operations.

In the above titled paper (ibid., vol. 56, no. 1, pp. 85-93, Mar 07), there were a number of errors. A list of corrections is presented here.

This paper describes several experiments performed by our research group to show the use of smartphones in physics teaching. We document our work on the development of apps for smartphones and on how to use recorded sensor data. As a final result, some interesting outcomes are obtained from the surveys conducted on the students about the use of these applications and their mLearning experience in general. These results show that the students are very interested in using smartphones as a complement to a more traditional learning. Finally, the influence of using the developed applications on students' grades and engagement was also analyzed. The results of this analysis prove that the use of smartphones highly improves students' engagement.

A new magnetorheological piston head design inspired by toroidal electromagnets was proposed in previous work as an alternative to conventional annular dampers. A prototype with a circular valve array integrated inside the piston head was built and tested to measure its passive performance. The mechanical, electromagnetic, and hydraulic models used in the new design were explained, and the relevant parameters of the actuator were analyzed to construct a mathematical model to estimate its performance. These works showed the feasibility of the concept and its potential as an alternative to current damper technology, but lacked a baseline for comparison. This paper reviews and widens this groundwork. It adds a magnetic finite element method study to address the previously found leakage, and a new set of experiments, including a force controller, to compare its performance against a conventional annular piston head. The new findings show how the current force limitations can be overcome by striking a balance between the coil space and the size of electromagnet cores to achieve the performance of current dampers. They also highlight its potential in force control applications to provide a wider range of customization options, such as number and size of holes, electromagnets, and coils, and a better use of the active area of the gap.

The title of this paper could possibly be misleading in that it suggests that we already have a solution for a problem which is still open or at least a conclusion from an investigation which is still under way.Accordingly, we should define straight away, subject to subsequent elaboration, (a) what we mean by an ‘advanced terminal area’, (b) what in such a context could be envisaged in terms of advantages for the aviation community, namely both the airspace users and the air traffic authorities, and finally (c) what new tools, both in the air and on the ground, would be desirable or essential in order to achieve a given degree of progress.

Seismic design should quantitatively evaluate and control the risk of earthquake-induced collapse that a building structure may experience during its design service life. This requires taking into consideration both the collapse resistant capacity of the building and the earthquake ground motion demand. The fundamental concept of uniform-risk-targeted seismic design and its relevant assessment process are presented in this paper. The risks of earthquake-induced collapse for buildings located in three seismic regions with the same prescribed seismic fortification intensity but different actual seismic hazards are analyzed to illustrate the engineering significance of uniform-risk-targeted seismic design. The results show that with China’s current seismic design method, the risk of earthquake-induced collapse of buildings varies greatly from site to site. Additional research is needed to further develop and implement the uniform-risk-targeted seismic design approach proposed in this paper.

In this paper, a class of non-linear time-varying delay systems with non-linear uncertainties is considered, where the input is distributed to the system non-linearly. A sliding-mode observer is designed by constructively utilizing the structure of the uncertainties. The sliding motion associated with the error dynamics is uniformly asymptotically stable and insensitive to the uncertainties. Then, based on the observer, a non-linear discontinuous control scheme is synthesized to stabilize the system uniformly asymptotically. The Lyapunov–Razumikhin approach is used to deal with the time delay. Both the bound on the uncertainty and the known non-linear term are fully used in the observer and controller design to reduce conservatism. A numerical example is given to illustrate the proposed approach. Simulation results demonstrate the efficiency of the obtained results.

Fuel oil viscosity is mainly affected by temperature, and however fuel oil temperature is a large inertia variable. Using PID control algorithm, may leads to certain over regulation in the control process. Based on the principle of thermodynamics and heat transfer, starting from establishing mathematical model of temperature control system, the fuel oil temperature PID control was studied in this paper. Further more, the control process MATLAB/Simulink simulation was carried out, with a resultant precise simulation figure. This provides a comparable reference to further improving for fuel oil temperature control process.

Active side sticks offer the possibility to adjust the force-feel characteristics to account for various piloting tasks and flight conditions. This promises a decrease in pilot workload and an increase in handling qualities. However, the optimum force-feel characteristics are not well understood and modeled; therefore, their tuning still rely on experimental methods. Experimental pilot-in-the-loop methods are time-consuming, expensive and have to be repeated with every change in control law dynamics. If a purely mathematical method for force characteristics optimization could be developed based on a better understanding of the principles underlying good force-feel systems, then the optimization could be done more efficiently and offline. This paper presents our current developments and achievements towards this new understanding to assess if and how a purely mathematical method could be derived from selected experiments. Even if this final goal could not be derived yet, the paper presents the selected approach and the lessons learned so far. More precisely, a simulator-based experiment was developed to provide the data for the later analyses and the identification of mathematical models suitable for that purpose. For this experiment, a roll tracking task is considered whose evaluation is based on both a qualitative (Cooper–Harper rating) and a quantitative criterion. The very encouraging results obtained so far on this scenario are detailed.

Managing the increased complexity, emerging uncertainties, and diversity of cultures on global projects is creating significant challenges for architecture, engineering, and construction firms. In global projects, differences in "institutions"—including language, beliefs, values, group norms, work practices, professional roles, industry organizations, and legal frameworks—among team members from different national backgrounds can lead to misunderstanding and conflicts that cause delays, increase costs, and reduce quality. Previous research has examined risk factors associated with international project execution. However, little research to date has explored whether reconfiguring project networks might mitigate such risks. Project organizational simulation tools have been combined with "robust design" experimental techniques to design robust project networks that can perform reliably in uncertain conditions. This paper extends project network design research to examine whether robust designs for given project networks differ between "domestic" and "global" projects, given differing organizational uncertainties. The results demonstrate that robust project network designs may differ for global project networks. This finding has significant implications for the design of project networks in an industry where firm participation in global project networks is increasing, both domestically and abroad.

A domestic water heating system that combines photovoltaic thermal (PVT) solar collectors with two heat pumps, in a novel cascade arrangement, is presented and analyzed in this paper. The goal of this analysis is to determine and compare the annual thermal energy output of the PVT cascade heat pump system with an evacuated tube and simultaneous consumption PVT single heat pump water heating system. The computational technique that was developed to analyze the PVT cascade heat pump system, which determines solar panel energy outputs, and heat pump operating characteristics, is described in detail. Case study simulation results are also presented, which include transient power output profiles, temperature profiles, and yearly energy output results. Hourly weather data, including air dry-bulb temperatures and solar flux values, from locations with a range of climates was used in these simulations. The results of this study show that the PVT cascade heat pump system has an annual thermal energy output improvement over the evacuated tube heating system ranging from 37% to 68%, depending on the selected simulation location.

The paper proposes a multidisciplinary design optimization (MDO) of permanent magnet synchronous generators (PMSG) for wind energy conversion systems (WECS). Such a MDO seeks the best compromise between the PMSG cost and the lifetime energy production of the WECS. So far, most of the papers in this field presented design methods using quite a few optimization variables and requiring a lot of assumptions. In the proposed MDO the specifications consist of geometrical, economical, magnetic, electrical and thermal constraints. Several analytic and semi-analytic sub-models where used to deal with these constraints, resulting in a large non-linear optimization problem that uses a sequential quadratic programming optimization algorithm. The paper considers the annual wind profile to estimate the lifetime wind turbine energy production. Moreover, the best possible solutions are presented in a Pareto front showing the trade-off between the generator cost and the wind turbine energy production. Among them, one optimal solution machine was chosen to be further investigated and its results were verified by finite element analysis.