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Industrial energy efficiency is stated as a major means of reducing the threat of increased global warming, caused by human use of fossil fuels. Energy service companies (ESCOs) have been expected to play an important role in promoting energy efficiency in different sectors of the economy, including industry. Energy related outsourcing in the complex energy intensive pulp and paper industry, with a continuous production process, represents one of the more challenging types of industrial outsourcing. This paper studies the role of ESCOs as a method to promote energy efficiency in the Swedish pulp and paper industry. A questionnaire was used, complemented by in-depth interviews with mill executives in order to gain more knowledge of the issue. The main conclusion from this paper is that the utilization of ESCOs in the pulp and paper industry is higher in activities with a lower level of energy integration in the production process, and on the contrary, the utilization of ESCOs is lower with a higher level of energy integration in the production process. Since the PPI is a mature industry with a globally well-known and well-spread technique, results from this paper, may plausibly be generalized for PPIs in other countries as well., ©2011 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Patrik Thollander and Mikael Ottosson, Energy related outsourcing: - The case of ESCOs in the Swedish pulp and paper industry, 2011, IEEE International Technology Management Conference, 329-337. http://dx.doi.org/10.1109/ITMC.2011.5995962

Industrial energy efficiency is stated as a major means of reducing the threat of increased global warming, caused by human use of fossil fuels. Energy service companies (ESCOs) have been expected to play an important role in promoting energy efficiency in different sectors of the economy, including industry. Energy related outsourcing in the complex energy intensive pulp and paper industry, with a continuous production process, represents one of the more challenging types of industrial outsourcing. This paper studies the role of ESCOs as a method to promote energy efficiency in the Swedish pulp and paper industry. A questionnaire was used, complemented by in-depth interviews with mill executives in order to gain more knowledge of the issue. The main conclusion from this paper is that the utilization of ESCOs in the pulp and paper industry is higher in activities with a lower level of energy integration in the production process, and on the contrary, the utilization of ESCOs is lower with a higher level of energy integration in the production process. Since the PPI is a mature industry with a globally well-known and well-spread technique, results from this paper, may plausibly be generalized for PPIs in other countries as well., ©2011 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Patrik Thollander and Mikael Ottosson, Energy related outsourcing: - The case of ESCOs in the Swedish pulp and paper industry, 2011, IEEE International Technology Management Conference, 329-337. http://dx.doi.org/10.1109/ITMC.2011.5995962

Industrial energy efficiency is stated as a major means of reducing the threat of increased global warming, caused by human use of fossil fuels. Energy service companies (ESCOs) have been expected to play an important role in promoting energy efficiency in different sectors of the economy, including industry. Energy related outsourcing in the complex energy intensive pulp and paper industry, with a continuous production process, represents one of the more challenging types of industrial outsourcing. This paper studies the role of ESCOs as a method to promote energy efficiency in the Swedish pulp and paper industry. A questionnaire was used, complemented by in-depth interviews with mill executives in order to gain more knowledge of the issue. The main conclusion from this paper is that the utilization of ESCOs in the pulp and paper industry is higher in activities with a lower level of energy integration in the production process, and on the contrary, the utilization of ESCOs is lower with a higher level of energy integration in the production process. Since the PPI is a mature industry with a globally well-known and well-spread technique, results from this paper, may plausibly be generalized for PPIs in other countries as well., ©2011 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Patrik Thollander and Mikael Ottosson, Energy related outsourcing: - The case of ESCOs in the Swedish pulp and paper industry, 2011, IEEE International Technology Management Conference, 329-337. http://dx.doi.org/10.1109/ITMC.2011.5995962

Industrial energy efficiency is stated as a major means of reducing the threat of increased global warming, caused by human use of fossil fuels. Energy service companies (ESCOs) have been expected to play an important role in promoting energy efficiency in different sectors of the economy, including industry. Energy related outsourcing in the complex energy intensive pulp and paper industry, with a continuous production process, represents one of the more challenging types of industrial outsourcing. This paper studies the role of ESCOs as a method to promote energy efficiency in the Swedish pulp and paper industry. A questionnaire was used, complemented by in-depth interviews with mill executives in order to gain more knowledge of the issue. The main conclusion from this paper is that the utilization of ESCOs in the pulp and paper industry is higher in activities with a lower level of energy integration in the production process, and on the contrary, the utilization of ESCOs is lower with a higher level of energy integration in the production process. Since the PPI is a mature industry with a globally well-known and well-spread technique, results from this paper, may plausibly be generalized for PPIs in other countries as well., ©2011 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Patrik Thollander and Mikael Ottosson, Energy related outsourcing: - The case of ESCOs in the Swedish pulp and paper industry, 2011, IEEE International Technology Management Conference, 329-337. http://dx.doi.org/10.1109/ITMC.2011.5995962

Industrial energy efficiency is stated as a major means of reducing the threat of increased global warming, caused by human use of fossil fuels. Energy service companies (ESCOs) have been expected to play an important role in promoting energy efficiency in different sectors of the economy, including industry. Energy related outsourcing in the complex energy intensive pulp and paper industry, with a continuous production process, represents one of the more challenging types of industrial outsourcing. This paper studies the role of ESCOs as a method to promote energy efficiency in the Swedish pulp and paper industry. A questionnaire was used, complemented by in-depth interviews with mill executives in order to gain more knowledge of the issue. The main conclusion from this paper is that the utilization of ESCOs in the pulp and paper industry is higher in activities with a lower level of energy integration in the production process, and on the contrary, the utilization of ESCOs is lower with a higher level of energy integration in the production process. Since the PPI is a mature industry with a globally well-known and well-spread technique, results from this paper, may plausibly be generalized for PPIs in other countries as well., ©2011 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Patrik Thollander and Mikael Ottosson, Energy related outsourcing: - The case of ESCOs in the Swedish pulp and paper industry, 2011, IEEE International Technology Management Conference, 329-337. http://dx.doi.org/10.1109/ITMC.2011.5995962

The paper considers the issue of activating inactive terminals by control signaling in the downlink in a massive MIMO system. There are two basic difficulties with this. First, the lack of CSI at the transmitter. Second, the short coherence interval, which limits the number of orthogonal pilots in the case of many antennas. The proposed scheme deals with these issues by repeating the transmission over the antennas. We show that this repetition does not affect the spectral efficiency significantly, while making it possible to estimate the channel in a standard way using MMSE. The paper also sheds some light the uplink-downlink power balance in massive MIMO.

The paper considers the issue of activating inactive terminals by control signaling in the downlink in a massive MIMO system. There are two basic difficulties with this. First, the lack of CSI at the transmitter. Second, the short coherence interval, which limits the number of orthogonal pilots in the case of many antennas. The proposed scheme deals with these issues by repeating the transmission over the antennas. We show that this repetition does not affect the spectral efficiency significantly, while making it possible to estimate the channel in a standard way using MMSE. The paper also sheds some light the uplink-downlink power balance in massive MIMO.

The paper considers the issue of activating inactive terminals by control signaling in the downlink in a massive MIMO system. There are two basic difficulties with this. First, the lack of CSI at the transmitter. Second, the short coherence interval, which limits the number of orthogonal pilots in the case of many antennas. The proposed scheme deals with these issues by repeating the transmission over the antennas. We show that this repetition does not affect the spectral efficiency significantly, while making it possible to estimate the channel in a standard way using MMSE. The paper also sheds some light the uplink-downlink power balance in massive MIMO.

The paper considers the issue of activating inactive terminals by control signaling in the downlink in a massive MIMO system. There are two basic difficulties with this. First, the lack of CSI at the transmitter. Second, the short coherence interval, which limits the number of orthogonal pilots in the case of many antennas. The proposed scheme deals with these issues by repeating the transmission over the antennas. We show that this repetition does not affect the spectral efficiency significantly, while making it possible to estimate the channel in a standard way using MMSE. The paper also sheds some light the uplink-downlink power balance in massive MIMO.

The paper considers the issue of activating inactive terminals by control signaling in the downlink in a massive MIMO system. There are two basic difficulties with this. First, the lack of CSI at the transmitter. Second, the short coherence interval, which limits the number of orthogonal pilots in the case of many antennas. The proposed scheme deals with these issues by repeating the transmission over the antennas. We show that this repetition does not affect the spectral efficiency significantly, while making it possible to estimate the channel in a standard way using MMSE. The paper also sheds some light the uplink-downlink power balance in massive MIMO.

HTTP-based Adaptive Streaming (HAS) has become a widely-used video delivery technology. Use of HTTP enables relatively easy firewall/NAT traversal and content caching. While caching is an important aspect of HAS, there is not much public research on the performance impact proxies and their policies have on HAS. In this paper we build an experimental framework using open source Squid proxies and the most recent Open Source Media Framework (OSMF). A range of content-aware policies can be implemented in the proxies and tested, while the player software can be instrumented to measure performance as seen at the client. Using this framework, the paper makes three main contributions. First, we present a scenario-based performance evaluation of the latest version of the OSMF player. Second, we quantify the benefits using different proxy-assisted solutions, including basic best effort policies and more advanced content quality aware prefetching policies. Finally, we present and evaluate a cooperative framework in which clients and proxies share information to improve performance. In general, the bottleneck location and network conditions play central roles in which policy choices are most advantageous, as they significantly impact the relative performance differences between policy classes. We conclude that careful design and policy selection is important when trying to enhance HAS performance using proxy assistance.

The higher penetration rate of GPS-enabled smartphones together with their improved processing power and battery life makes them suitable for a number of participatory sensing applications. The purpose of this paper is to analyse how GPS-enabled smartphones can be used in a participatory sensing context to build a radio map for RSS-based positioning, with a special focus on road traffic information based on cellular network signalling. The CEP-67 location accuracy achieved is 75 meters for both GSM and UMTS using Bayesian classification. For this test site, the accuracy is similar for GSM and UMTS, with slightly better results for UMTS in the CEP-95 error metric. The location accuracy achieved is good enough to avoid large errors in travel time estimation for highway environments, especially considering the possibility to filter out estimates with low accuracy using for example the posterior bin probability in Bayesian classification. For urban environments more research is required to determine how the location accuracy will affect the path inference problem in a dense road network. The location accuracy achieved in this paper is also sufficient for other traffic information types, for example origin-destination estimation based on location area updates.

State-of-the-art object detectors typically use shape information as a low level feature representation to capture the local structure of an object. This paper shows that early fusion of shape and color, as is popular in image classification, leads to a significant drop in performance for object detection. Moreover, such approaches also yields suboptimal results for object categories with varying importance of color and shape. In this paper we propose the use of color attributes as an explicit color representation for object detection. Color attributes are compact, computationally efficient, and when combined with traditional shape features provide state-of-the-art results for object detection. Our method is tested on the PASCAL VOC 2007 and 2009 datasets and results clearly show that our method improves over state-of-the-art techniques despite its simplicity. We also introduce a new dataset consisting of cartoon character images in which color plays a pivotal role. On this dataset, our approach yields a significant gain of 14% in mean AP over conventional state-of-the-art methods., CUAS

This paper introduces a realization of finite-length impulse response (FIR) filters with simultaneously variable bandwidth and fractional delay (FD). The realization makes use of impulse responses which are two-dimensional polynomials in the bandwidth and FD parameters. Unlike previous polynomial-based realizations, it utilizes the fact that a variable FD filter is typically much less complex than a variable-bandwidth filter. By separating the corresponding subfilters in the overall realization, significant savings are thereby achieved. A design example, included in the paper, shows about 65 percent multiplication and addition savings compared to the previous polynomial-based realizations. Moreover, compared to a recently introduced alternative fast filter bank approach, the proposed method offers significantly smaller group delays and group delay errors.

Complex transmission concepts may enable high fuel efficiency but require much effort in controller development. This effort should only be spent if the potential of the concept if high, a potential which can be determined using optimization techniques. This paper examine the use of stochastic dynamic programming for transmission potential evaluation, applied on a wheel loader. The concepts evaluated is the present automatic gearbox and a multi-mode CVT (MM-CVT). A probabilistic driving cycle is created from a measurement including 34 loading cycles. Trajectory optimization is performed both against probabilistic and deterministic cycles. The paper shows that the introduction of a probabilistic load highly affect the application of optimization. It is also shown that the MM-CVT has approximately 20% lower minimum fuel requirement than the present transmission, and that this number is not sensitive to the quality of the prediction.

The paper shows the implementation of digital FIR filter using ultra-low power logic components. Source coupled logic is used and operated at sub-threshold region to achieve low power consumption while keeping a satisfactory output swing. The STSCL (sub-threshold source coupled logic) circuit is added with controllable voltage-level feature to minimize overall leakage current flow, including both gate leakage and sub-threshold. Seven-stage ring oscillators are implemented in CMOS, STSCL and our proposed logic at similar supply voltage to observe the differences with power consumption for the proposed technique came at nW range. Later on the FIR was design in both CMOS and proposed with measurement results shown in the paper. All measurements for are shown using 65 nm process technology, at a supply voltage of 0.5 V.

Performing large scale physical experiments to evaluate the packet delivery ratio, latency, and resource utilization in mobile ad hoc networks is a costly and difficult exercise. A more cost-effective method of performing trade-off studies in connection with protocol evaluations is simulation. However, simulations are often time consuming and require a detailed description of a given scenario’s mobility and topology. A more general approach for scalability and performance studies is the use of abstract models of behavior in networks of mobile nodes. This paper illustrates the power of such a model by illustrating the prediction capability of the Forward-Wait framework with respect to the routing performance of geographic delay-tolerant routing. The Forward-Wait mathematical framework describes packet movements as a sequence of alternating forwarding and waiting phases. Key input parameters to the Forward-Wait framework are distributions describing the forwarding and waiting phases, and the source destination distance. The paper shows how these distributions can be derived and used to predict the routing performance in different scenarios and a variety of network sizes.

Haptics has in earlier work shown the potential to assist in the understanding of an otherwise overwhelming amount of information in scientific and medical visualization. In the typical scientific data, with many different properties such as pressure, temperature, strain, etc, the user is required to switch between what data to represent through the haptic feedback. In this paper we explore the possibility to simultaneously represent, in a comprehensive way, more than one property through the haptic feedback by dividing the feedback into the two components of the haptic sense. Two vibrotactile metaphors for scalar data are described, roughness and transition cue, that can be used in combination with a kinaesthetic representation of either scalar or vector data. The paper also presents an evaluation that shows that the individual cues from the two haptic metaphors can be discriminated, and that the combined feedback can be used to find combinations of features in data.

The research within this paper identifies three main categories of cross-cultural communication challenges within international transfer of aircraft production. The first category is organizational structure, hierarchy and delegation of responsibility the second category is consensus behavior and avoidance of conflicts and the third category is individual motivation factors. Furthermore, the paper discusses the need for specific types of cross-cultural training that can be one solution for reducing the problems and difficulties that cultural challenges may induce. The case study indicates that it is important for Aeronautics, a Swedish enterprise, to apply organized cross-cultural training in combination with technical training. To secure the presence of cross-cultural training, suitable types of cultural training could be included in the working process/routine for how to conduct a production transfer.

This paper presents a component based wireless monitoring and control system. The system is introduced from both the system architecture and function point of view. The paper begins with the introduction of the component design and the communication interaction between them. The system is composed by three components, the wireless sensor network, the local server and the main server. Wireless sensor networks are deployed in different locations for remote monitoring and control purpose. The monitoring results and control commands are synchronized between the main server and wireless sensor networks via local servers. The test results of the battery life time calculation and remote monitoring field test results are presented in the end of the paper.

Time-triggered periodic control implementations are over provisioned for many execution scenarios in which the states of the controlled plants are close to equilibrium. To address this inefficient use of computation resources, researchers have proposed self-triggered control approaches in which the control task computes its execution deadline at runtime based on the state and dynamical properties of the controlled plant. The potential advantages of this control approach cannot, however, be achieved without adequate online resource-management policies. This paper addresses scheduling of multiple self-triggered control tasks that execute on a uniprocessor platform, where the optimization objective is to find tradeoffs between the control performance and CPU usage of all control tasks. Our experimental results show that efficiency in terms of control performance and reduced CPU usage can be achieved with the heuristic proposed in this paper.

In this paper we address the replication versusredundancy optimisation problem for a class of intermittentlyconnectedad hoc networks with the following three characteristics:routing is performed by a store-carry-forward mechanismin an opportunistic manner, replication of custodian messagesis used to increase the delivery ratio, and fragmentationcombined with redundancy in the form of erasure coding isused to deal with large messages in short contact windows.We propose a novel mathematical model in which the meritsof a high replication factor can be compared to a high levelof redundancy in erasure coding. The purpose of the model isto identify the optimised level of replication and redundancyas a function of application-specific parameters like messagesize and time-to-live. Our model builds upon a componentfor message latency distribution that we have borrowed fromearlier works (SprayAndWait) and that has been extended forerasure coding and constrained resources. The model is generaland can be applied in different opportunistic settings using thefollowing approach. First, we derive a set of equations that aredemonstrated to identify the optimal replication and redundancyfactor in a network with constrained resources. Then,the paper includes an extension that provides a tailormadelatency distribution based on history profiling, thus making itapplicable to any protocol that uses replication/redundancy ina similar network. By theoretical analysis and simulations, wedemonstrate that using erasure coding together with replicationoffers an efficient yet flexible tradeoff between resource costand protocol performance.

Incident post-mortem analysis after recovery from incidents is recommended by most incident response experts. An analysis of why and how an incident happened is crucial for determining appropriate countermeasures to prevent the recurrence of the incident. Currently, there is a lack of structured methods for such an analysis, which would identify the causes of a security incident. In this paper, we present a structured method to perform the post-mortem analysis and to model the causes of an incident visually in a graph structure. This method is an extension of our earlier work on modeling software vulnerabilities. The goal of modeling incidents is to develop an understanding of what could have caused the security incident and how its recurrence can be prevented in the future. The method presented in this paper is intended to be used during the post-mortem analysis of incidents by incident response teams.

The existence of market power is a serious concern in modern electric energy markets. Systems and processes that monitor the trading is needed and much research and many proposals on how to deal with the problem have been introduced over the past couple of years. A challenge to all such methods is execution speed, since the identification of market power needs to be done in real-time as market prices are settled. To overcome this challenge the methods need to be simple, involving limited computational effort. This paper presents a simple method with the potential of overcoming the challenge of execution speed. The method is based on the idea of determining the participants with the ability to make considerable increases in price raises without losing all market shares. Such determination can be made in advance during day ahead trading to identify critical areas. During realtime settlement, the method can then be used in a second iteration to study the identified critical areas. In the paper we propose a way to calculate the remaining market shares after a large price raise and refer to these as Monopolistic Energy Levels. These calculated levels of energy, that are deliverable by a single certain participant or by a certain group of participants, are caused by the active congestions in the network. The method detects the quantity of these energy levels and their respective locations in the network. This is a prospective method when used with a prediction of the following days demand. The paper presents the background and development of the proposed method. The use of AC and DC power flow as means to determine the monopolistic energy levels are analyzed and discussed. The paper is concluded with examples of application of the method to a simple multi area power system.

Operationally efficient radio networks typically feature a high degree of self-organization. This means less planning efforts and manual intervention, and a potential for better radio resource utilization when network elements adapts its operation to the observed local conditions. The focus in this paper is selfoptimization of the random access channel (RACH) in the 3G Long Term Evolution (LTE). A comprehensive tutorial about the RACH procedure is provided to span the complexity of the selfoptimization. Moreover, the paper addresses RACH key performance metrics and appropriate modeling of the various steps and components of the procedure. Finally, some coupling between parameters and key performance metrics as well as selfoptimization examples are presented together with a feasibility discussion. The main ambition with this workshop paper is to present and define a relevant set of self-optimization problems, rather than to provide a complete solution.

In intermittently connected ad hoc networks standard routing protocols like AODV, DSR and GPSR fail since they generally cannot find a contemporaneous path from source to destination. In this paper we present LAROD, a geographical routing protocol for intermittently connected networks. Combining beacon less geographical routing with store-carry-forward LAROD greedily searches for the shortest way to the destination and when no progress is possible packets are temporarily stored until node mobility has created a new path. In the paper we have shown by a comparative study that LAROD has almost as good delivery rate as an epidemic routing scheme, but at a substantially lower overhead.

This paper introduces a multi-mode transmultiplexer (TMUX) consisting of Farrow-based variable integer sampling rate conversion (SRC) blocks. The polyphase components of general interpolation/ decimation filters are realized by the Farrow structure making it possible to achieve different linear-phase finite-length impulse response (FIR) lowpass filters at the cost of a fixed set of subfilters and adjustable fractional delay values. Simultaneous design of the subfilters, to achieve overall approximately Nyquist (Mth-band) filters, are treated in this paper. By means of an example, it is shown that the subfilters can be designed so that for any desired range of integer SRC ratios, the TMUX can approximate perfect recovery as close as desired., Original publication: Amir Eghbali, Håkan Johansson and Per Löwenborg, A farrow-structure-based multi-mode transmultiplexer, 2008, Proceedings of IEEE International Symposium on Circuits and Systems, Seattle, Washington, USA, May. 18-21, pp3114-3117. http://dx.doi.org/10.1109/ISCAS.2008.4542117. Copyright: IEEE, http://www.ieee.org

This paper presents a linear minimum mean square error (LMMSE) symbol detector for MIMO-OFDM enabled mobile terminals. The detector is implemented using a programmable baseband processor aimed for software-defined radio (SDR). Owing to the dynamic range supplied by the floating-point SIMD datapath, special algorithms can be adopted to reduce the computational latency of detection. The programmable solution not only supports different transmit/receive antenna configurations, but also allows hardware multiplexing to obtain silicon and power efficiency. Compared to several existing fixed-functional solutions, the one proposed in this paper is smaller, more flexible and faster.

Radio network management simplification concerns to some extent the removal, not the simplification, of tasks. In this paper we present an approach for automatic network management in 3G long term evolution (LTE), namely, methods for automatic configuration of locally-unique physical cell identities and neighbor cell relation lists. We show that these issues can be removed from the list of planning tasks and completely replaced by autonomous algorithms. These algorithms make use of mobile measurements to detect local cell identity conflicts, resolve them, and to update the neighbor cell relation lists in the cells. The performance of the approach is determined using simulations of realistically deployed macro networks. The simulations illustrate the ability of the algorithms to resolve local cell identity conflicts. In particular, the algorithms are capable of both accommodating new cells and handling a worst case scenario where all cells are initiated with the same local cell identities and where neighbor cell relation lists are empty. The contributions in this paper are meant to aid operators by allowing them to replace time consuming and costly tasks with automatic mechanisms, thus, reducing operational expenditure.

Advances in both microelectronics and wireless commu- nication technology have made it possible to develop and manufacture low cost and energy efficient sensor nodes. To compare different designs and protocols with respect to both energy and delay constraints an energy dissipation model is needed that takes these aspects into account. In this paper we propose a complete energy dissipation model for wire- less sensor networks that uses four operation states. These states are based on the basic sensor nodes architecture and actual working conditions of a sensor node. It also takes into account the transition between the operation states, such that a decision to change operation state can be more accurately determined. In this paper we also present mea- sured values for both the power consumed in each operation state and the time it takes to complete a transition between two operation states.

This paper describes the use of programmable microwave function array (PROMFA) for different microwave application. The PROMFA concept is based on an array of generic cells, in which a number of different functions can be realized. Each PROMFA cell is a four-port circuit, that can either be programmed independently or collectively according to a specific need. Specifically, the phase shift capability in a single PROMFA cell, useful for a new type of phase shifter design is discussed. The paper also presents the functionality of this new architecture as a beamforming network. As an example case an active corporate feed network and a tunable recursive filter is demonstrated. Simulated and measured results are presented.

Advances in both microelectronics and wireless commu- nication technology have made it possible to develop and manufacture low cost and energy efficient sensor nodes. To compare different designs and protocols with respect to both energy and delay constraints an energy dissipation model is needed that takes these aspects into account. In this paper we propose a complete energy dissipation model for wire- less sensor networks that uses four operation states. These states are based on the basic sensor nodes architecture and actual working conditions of a sensor node. It also takes into account the transition between the operation states, such that a decision to change operation state can be more accurately determined. In this paper we also present mea- sured values for both the power consumed in each operation state and the time it takes to complete a transition between two operation states.

Recently lattice-reduction aided decoders have been proposed in MIMO system to achieve near Maximum Likelihood decoder performance while maintaining reasonable complexity. This paper studies the implementation of lattice-reduction aided linear decoders on a programmable device for multi-user space-time block coding (MU-STBC). By reloading software, the device can be configured to use different decoding schemes according to the amount of resources available, which is an important feature of cognitive radio. In this paper, two different lattice-reduction aided linear decoding methods namely SQRD-LR and AQRD-LR for MU-STBC are evaluated based on their BER performance and computational complexity. Furthermore, the effect of deadline constraint on LR is evaluated and based on the evaluation, a new method namely adaptive decoding is proposed by us to allow mode-switching of the decoder according to the environment parameters, so that the best decoder performance can always be achieved while fulfiling the resource constraints.

The size of standard volumetric data sets in medical imaging is rapidly increasing causing severe performance limitations in direct volume rendering pipelines. The methods presented in this paper exploit the medical knowledge embedded in the transfer function to reduce the required bandwidth in the pipeline. Typically, medical transfer functions cause large subsets of the volume to give little or no contribution to the rendered image. Thus, parts of the volume can be represented at low resolution while retaining overall visual quality. This paper introduces the use of transfer functions at decompression time to guide a level-of-detail selection scheme. The method may be used in combination with traditional lossy or lossless compression schemes. We base our current implementation on a multi-resolution data representation using compressed wavelet transformed blocks. The presented results using the adaptive decompression demonstrate a significant reduction in the required amount of data while maintaining rendering quality. Even though the focus of this paper is medical imaging, the results are applicable to volume rendering in many other domains.

Tensors and tensor fields are commonly used in multidimensional signal processing to represent the local structure of the signal. This paper focuses on the case where the sampling on the original signal is anisotropic, e.g when the resolution of the multidimensional image varies depending on the direction which is common e.g. in medical imaging devices. To obtain a geometrically correct description of the local structure there are mainly two possibilities. To resample the image prior to the computation of the local structure tensor field or to compute the tensor field on the original grid and transform the result to obtain a correct geometry of the local structure. This paper deals with the latter alternative and contains an in depth theoretical analysis establishing the appropriate rules for tensor transformations induced by changes in space-time geometry with emphasis on velocity and motion estimation.

Modelica is a general equation-based object-oriented language for continuous and discrete-event modeling of physical systems for the purpose of efficient simulation. The language unifies and generalizes previous objectoriented modeling languages. The Modelica modeling language and technology is being warmly received by the world community in modeling and simulation. It is bringing about a revolution in this area, based on its ease of use, visual design of models with combination of legolike predefined model building blocks, its ability to define model libraries with re-usable components and its support for modeling and simulation of complex applications involving parts from several application domains. In this paper we present the Modelica language with emphasis on its language features and one of the associated simulation environments. Simulation models can be developed in an integrated problem-solving environment by using a graphical editor for connection diagrams. Connections are established just by drawing lines between objects picked from a class library. The principles of object oriented physical systems modeling and the multi-domain capabilities of the language are presented in the paper by several examples.

Modelica is a general equation-based object-oriented language for continuous and discrete-event modeling of physical systems for the purpose of efficient simulation. The language unifies and generalizes previous objectoriented modeling languages. The Modelica modeling language and technology is being warmly received by the world community in modeling and simulation. It is bringing about a revolution in this area, based on its ease of use, visual design of models with combination of legolike predefined model building blocks, its ability to define model libraries with re-usable components and its support for modeling and simulation of complex applications involving parts from several application domains. In this paper we present the Modelica language with emphasis on its language features and one of the associated simulation environments. Simulation models can be developed in an integrated problem-solving environment by using a graphical editor for connection diagrams. Connections are established just by drawing lines between objects picked from a class library. The principles of object oriented physical systems modeling and the multi-domain capabilities of the language are presented in the paper by several examples.

Modelica is a general equation-based object-oriented language for continuous and discrete-event modeling of physical systems for the purpose of efficient simulation. The language unifies and generalizes previous objectoriented modeling languages. The Modelica modeling language and technology is being warmly received by the world community in modeling and simulation. It is bringing about a revolution in this area, based on its ease of use, visual design of models with combination of legolike predefined model building blocks, its ability to define model libraries with re-usable components and its support for modeling and simulation of complex applications involving parts from several application domains. In this paper we present the Modelica language with emphasis on its language features and one of the associated simulation environments. Simulation models can be developed in an integrated problem-solving environment by using a graphical editor for connection diagrams. Connections are established just by drawing lines between objects picked from a class library. The principles of object oriented physical systems modeling and the multi-domain capabilities of the language are presented in the paper by several examples.

Modelica is a general equation-based object-oriented language for continuous and discrete-event modeling of physical systems for the purpose of efficient simulation. The language unifies and generalizes previous objectoriented modeling languages. The Modelica modeling language and technology is being warmly received by the world community in modeling and simulation. It is bringing about a revolution in this area, based on its ease of use, visual design of models with combination of legolike predefined model building blocks, its ability to define model libraries with re-usable components and its support for modeling and simulation of complex applications involving parts from several application domains. In this paper we present the Modelica language with emphasis on its language features and one of the associated simulation environments. Simulation models can be developed in an integrated problem-solving environment by using a graphical editor for connection diagrams. Connections are established just by drawing lines between objects picked from a class library. The principles of object oriented physical systems modeling and the multi-domain capabilities of the language are presented in the paper by several examples.

Modelica is a general equation-based object-oriented language for continuous and discrete-event modeling of physical systems for the purpose of efficient simulation. The language unifies and generalizes previous objectoriented modeling languages. The Modelica modeling language and technology is being warmly received by the world community in modeling and simulation. It is bringing about a revolution in this area, based on its ease of use, visual design of models with combination of legolike predefined model building blocks, its ability to define model libraries with re-usable components and its support for modeling and simulation of complex applications involving parts from several application domains. In this paper we present the Modelica language with emphasis on its language features and one of the associated simulation environments. Simulation models can be developed in an integrated problem-solving environment by using a graphical editor for connection diagrams. Connections are established just by drawing lines between objects picked from a class library. The principles of object oriented physical systems modeling and the multi-domain capabilities of the language are presented in the paper by several examples.

Multi-user multiple-input multiple-output (MU-MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information (CSI) and M BS antennas. In particular, we consider two distinct operation modes, namely when the phase noise processes at the BS antennas are identical (synchronous operation) and when they are independent (non-synchronous operation). We analyze a linear and low-complexity time-reversal maximum-ratio combining (TR-MRC) reception strategy. For both operation modes we derive a lower bound on the sum-capacity and we compare the performance of the two modes. Based on the derived achievable sum-rate, we show that with the proposed receive processing an O() array gain is achievable. Due to the phase noise drift the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users., Manuscript received March 5, 2014; revised July 10, 2014; accepted September 6, 2014. Date of publication September 18, 2014; date of current version February 6, 2015. This work was supported in part by the Swedish Foundation for Strategic Research and in part by ELLIIT. The work of S. K. Mohammed was supported by the Science and Engineering Research Board, Department of Science and Technology, Government of India. This paper was presented in part at the 50th Allerton Conference on Communication, Control and Computing, Urbana-Champaign, IL, USA, October 2012. The associate editor coordinating the review of this paper and approving it for publication was L. Sanguinetti.

Multi-user multiple-input multiple-output (MU-MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information (CSI) and M BS antennas. In particular, we consider two distinct operation modes, namely when the phase noise processes at the BS antennas are identical (synchronous operation) and when they are independent (non-synchronous operation). We analyze a linear and low-complexity time-reversal maximum-ratio combining (TR-MRC) reception strategy. For both operation modes we derive a lower bound on the sum-capacity and we compare the performance of the two modes. Based on the derived achievable sum-rate, we show that with the proposed receive processing an O() array gain is achievable. Due to the phase noise drift the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users., Manuscript received March 5, 2014; revised July 10, 2014; accepted September 6, 2014. Date of publication September 18, 2014; date of current version February 6, 2015. This work was supported in part by the Swedish Foundation for Strategic Research and in part by ELLIIT. The work of S. K. Mohammed was supported by the Science and Engineering Research Board, Department of Science and Technology, Government of India. This paper was presented in part at the 50th Allerton Conference on Communication, Control and Computing, Urbana-Champaign, IL, USA, October 2012. The associate editor coordinating the review of this paper and approving it for publication was L. Sanguinetti.

Multi-user multiple-input multiple-output (MU-MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information (CSI) and M BS antennas. In particular, we consider two distinct operation modes, namely when the phase noise processes at the BS antennas are identical (synchronous operation) and when they are independent (non-synchronous operation). We analyze a linear and low-complexity time-reversal maximum-ratio combining (TR-MRC) reception strategy. For both operation modes we derive a lower bound on the sum-capacity and we compare the performance of the two modes. Based on the derived achievable sum-rate, we show that with the proposed receive processing an O() array gain is achievable. Due to the phase noise drift the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users., Manuscript received March 5, 2014; revised July 10, 2014; accepted September 6, 2014. Date of publication September 18, 2014; date of current version February 6, 2015. This work was supported in part by the Swedish Foundation for Strategic Research and in part by ELLIIT. The work of S. K. Mohammed was supported by the Science and Engineering Research Board, Department of Science and Technology, Government of India. This paper was presented in part at the 50th Allerton Conference on Communication, Control and Computing, Urbana-Champaign, IL, USA, October 2012. The associate editor coordinating the review of this paper and approving it for publication was L. Sanguinetti.

Multi-user multiple-input multiple-output (MU-MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information (CSI) and M BS antennas. In particular, we consider two distinct operation modes, namely when the phase noise processes at the BS antennas are identical (synchronous operation) and when they are independent (non-synchronous operation). We analyze a linear and low-complexity time-reversal maximum-ratio combining (TR-MRC) reception strategy. For both operation modes we derive a lower bound on the sum-capacity and we compare the performance of the two modes. Based on the derived achievable sum-rate, we show that with the proposed receive processing an O() array gain is achievable. Due to the phase noise drift the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users., Manuscript received March 5, 2014; revised July 10, 2014; accepted September 6, 2014. Date of publication September 18, 2014; date of current version February 6, 2015. This work was supported in part by the Swedish Foundation for Strategic Research and in part by ELLIIT. The work of S. K. Mohammed was supported by the Science and Engineering Research Board, Department of Science and Technology, Government of India. This paper was presented in part at the 50th Allerton Conference on Communication, Control and Computing, Urbana-Champaign, IL, USA, October 2012. The associate editor coordinating the review of this paper and approving it for publication was L. Sanguinetti.

For time division duplexing (TDD) systems, the physical channel in the air is reciprocal for uplink (UL) and downlink (DL) within the channel coherence time. However when the transceivers radio frequency (RF) hardware is taken into consideration, TDD channel reciprocity no longer holds because of the non-symmetric characteristics of RF transmit and receive chains. Relative calibration has been proposed to compensate this hardware impairment with a multiplicative matrix. In this paper we perform hardware measurements on this calibration matrix which gives a direct insight on the physical phenomenon of TDD transceivers. Especially, we inspect the assumption that this calibration matrix is diagonal, which is widely adopted in literature but has never been verified by experiments. This work can be regarded as an experimental base for TDD calibration or for theoretical analysis of non-perfect channel reciprocity of TDD systems.

Multi-user multiple-input multiple-output (MU-MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information (CSI) and M BS antennas. In particular, we consider two distinct operation modes, namely when the phase noise processes at the BS antennas are identical (synchronous operation) and when they are independent (non-synchronous operation). We analyze a linear and low-complexity time-reversal maximum-ratio combining (TR-MRC) reception strategy. For both operation modes we derive a lower bound on the sum-capacity and we compare the performance of the two modes. Based on the derived achievable sum-rate, we show that with the proposed receive processing an O() array gain is achievable. Due to the phase noise drift the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users., Manuscript received March 5, 2014; revised July 10, 2014; accepted September 6, 2014. Date of publication September 18, 2014; date of current version February 6, 2015. This work was supported in part by the Swedish Foundation for Strategic Research and in part by ELLIIT. The work of S. K. Mohammed was supported by the Science and Engineering Research Board, Department of Science and Technology, Government of India. This paper was presented in part at the 50th Allerton Conference on Communication, Control and Computing, Urbana-Champaign, IL, USA, October 2012. The associate editor coordinating the review of this paper and approving it for publication was L. Sanguinetti.

The 4G standard Long Term Evolution (LTE) has been developed for high-bandwidth mobile access for today's data-heavy applications, consequently, a better experience for the end user. Since cellular communication is ready available, LTE communication has been designed to work at high speeds for vehicular communication. The challenge is that the protocols in LTE/LTE-Advanced should not only provide good packet delivery but also adapt to changes in the network topology due to vehicle volume and vehicular mobility. It is a critical requirement to ensure a seamless quality of experience ranging from safety to relieving congestion as deployment of LTE/LTE-Advanced become common. This requires learning how to improve the LTE/LTE-Advanced model to better appeal to a wider base and move toward additional solutions. In this paper we present a feasibility analysis for performing vehicular communication via a queueing theory approach based on a multi-server queue using real LTE traffic. A M/M/m model is employed to evaluate the probability that a vehicle finds all channels busy, as well as to derive the expected waiting times and the expected number of channel switches. Also, when a base station (eNB) becomes overloaded with a single-hop, a multi-hop rerouting optimization approach is presented.

The 4G standard Long Term Evolution (LTE) has been developed for high-bandwidth mobile access for today's data-heavy applications, consequently, a better experience for the end user. Since cellular communication is ready available, LTE communication has been designed to work at high speeds for vehicular communication. The challenge is that the protocols in LTE/LTE-Advanced should not only provide good packet delivery but also adapt to changes in the network topology due to vehicle volume and vehicular mobility. It is a critical requirement to ensure a seamless quality of experience ranging from safety to relieving congestion as deployment of LTE/LTE-Advanced become common. This requires learning how to improve the LTE/LTE-Advanced model to better appeal to a wider base and move toward additional solutions. In this paper we present a feasibility analysis for performing vehicular communication via a queueing theory approach based on a multi-server queue using real LTE traffic. A M/M/m model is employed to evaluate the probability that a vehicle finds all channels busy, as well as to derive the expected waiting times and the expected number of channel switches. Also, when a base station (eNB) becomes overloaded with a single-hop, a multi-hop rerouting optimization approach is presented.

An oversampled digital-to-analog converter including digital Sigma Delta modulator and semi-digital FIR filter can be employed in the transmitter of the VDSL2 technology. To select the optimum set of coefficients for the semi-digital FIR filter, an integer optimization problem is formulated in this work, where the model includes the FIR filter magnitude metrics as well as Sigma Delta modulator noise transfer function. The semi-digital FIR filter is optimized with respect to magnitude constraints according to the International Telecommunication Union Power Spectral Density mask for VDSL2 technology and minimizing analog cost as the objective function. Utilizing the semi-digital FIR filter with one bit DACs, high linearity required in high-bandwidth profiles of VDSL2, can be achieved. The resolution of the conventional DACs are limited by the mismatch between DAC unit elements. By utilizing one-bit DACs in semi-digital FIR filter, there will be less degradation caused by mismatch between unit elements. The optimization problem is solved in two conditions; fixed passband gain and variable passband gain. It is shown in this paper that 38% saving in total number of unit elements can be achieved by employing variable passband gain in the optimization problem.

This paper presents a self-calibration technique for a fast-switching DLL-based frequency synthesizer targeting frequency-hopped ultra-wideband (UWB) communication. The proposed architecture employs the concept of track-and-hold (T/H) technique to sample the lock control voltages regarding each channel and store them across a corresponding capacitor during a start-up phase. During the normal operation when the hopping command arrives, the stored voltages are applied to the loop in an open-loop regime to perform fast channel switching of sub-9.5 ns which is required by WiMedia-UWB standard. Certain architectural and circuit methods are utilized in order to minimize the error in the sampled voltages caused by channel charge injection and clock feedthrough of the sampling switches. Since the proposed fast-switching scheme does not require a wide loop bandwidth, the existing tradeoff in phase-locked systems between the settling time and the control voltage ripples resulting in sideband spurs is eliminated. Moreover, the VCDL can be biased in the low-gain region of its transfer function to reduce its noise transfer to the synthesizer output. The proposed architecture is implemented in a 65-nm standard CMOS process and the simulation results indicate a worst-case band switching time of less than 5.5 ns.