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In this paper, an extended fast factorized back projection (FFBP) algorithm is proposed to focus the missile-borne bistatic forward-looking synthetic aperture radar (BFSAR) data. It is also based on the subaperture processing technique to reduce the computational burden, but represents the subimages on the elliptical polar coordinates referenced to the tracks of both transmitter and receiver. First, the imaging geometry and signal model of the missile-borne BFSAR are established. Then, considering the special configuration of the missile-borne BFSAR, a novel elliptical polar coordinate system whose origin is determined by the positions of both transmitter and receiver is established. The subaperture processing approach based on this coordinate system is presented. Successively, based on the range error analysis, the sampling requirements of the elliptical polar subimages are derived to provide a tradeoff between the imaging quality and efficiency. Finally, the computational burden of the proposed algorithm is discussed, and the speed-up factor of the proposed algorithm with respect to the direct back projection algorithm is derived. The experimental results with simulated data prove the validity and feasibility of the proposed algorithm. [ABSTRACT FROM AUTHOR]

An error-erasure channel is a simple noise model that introduces both errors and erasures. While the two types of errors can be corrected simultaneously with error-correcting codes, it is also known that any linear code allows for first correcting errors and then erasures in two-step decoding. In particular, a carefully designed parity-check matrix not only allows for separating erasures from errors but also makes it possible to efficiently correct erasures. The separating redundancy of a linear code is the number of parity-check equations in a smallest parity-check matrix that has the required property for this error-erasure separation. In a sense, it is a parameter of a linear code that represents the minimum overhead for efficiently separating erasures from errors. While several bounds on separating redundancy are known, there still remains a wide gap between upper and lower bounds except for a few limited cases. In this paper, using probabilistic combinatorics and design theory, we improve both upper and lower bounds on separating redundancy. We also show a relation between parity-check matrices for error-erasure separation and special matrices, called X-codes, for data compaction circuits in VLSI testing. This leads to an exponentially improved bound on the size of an optimal X-code. [ABSTRACT FROM AUTHOR]

This paper obtains the first degrees of freedom (DoFs) bound that is provably sensitive tonetworkcoherence time, i.e., coherence time in an interference network, where all channels experience the same coherence patterns. This is accomplished by a novel adaptation of the aligned image sets bound and settles various open problems noted previously by Naderi and Avestimehr and by Gouet al.For example, a necessary and sufficient condition is obtained for the optimality of 1/2 DoF per user in a partially connected interference network, where the channel state information at the receivers (CSIRs) is perfect, the channel state information at the transmitters (CSITs) is instantaneous but limited to finite precision, and the network coherence time is $T_{c}=1$. The surprising insight that emerges is that even with perfect CSIR and instantaneous finite precision CSIT, the network coherence time matters, i.e., it has a DoF impact. [ABSTRACT FROM AUTHOR]

Detecting equivalence classes of injected faults for functional verification of electronic systems is an important task because it helps reducing the number of faults to qualify a verification environment, and hence, improves the performance of qualification process and the validation time required for large-scale electronic systems. This paper describes an efficient way of detecting equivalent injected faults in a mapped netlist in order to speedup the qualification process of a verification environment for functional safety. The presented fault models include general faults resulting in arbitrary functional changes, in addition to conventional stuck-at faults. The solution is based on structural pruning and functional analysis performed by a synergistic combination of iterative Boolean satisfiability and guided simulation. It should be noted that traditional brute-force-like methods would take many hours or even days to identify thousands of equivalent functional faults injected to a small circuit with only hundred of cells. The proposed approach can achieve excellent fault reduction ratios within few seconds for such small circuits. The implementation also scales well for the largest ISCAS’89 and OpenCores benchmarks containing over 35K gates and 490K general functional faults. [ABSTRACT FROM AUTHOR]

In this paper, we propose a combined full duplex (FD)- and half duplex (HD)-based transmission and channel acquisition model for an open-loop multiuser multiple-input multiple-output (MIMO) systems. Assuming residual self-interference at the base station (BS), the idea is to utilize the FD mode during the uplink (UL) training phase in order to achieve simultaneous downlink (DL) data transmission and UL CSI acquisition. More specifically, the BS begins serving a user when its CSI becomes available, while at the same time, it also receives UL pilots from the next scheduled user. We investigate both zero-forcing (ZF) and maximum ratio transmission MIMO beamforming techniques for the DL data transmission in the FD mode. The BS switches to the HD mode once it receives the CSI of all users and it employs ZF beamforming for the DL data transmission until the end of the transmission frame. Furthermore, we derive closed-form approximations for the lower bounded ergodic achievable rate relying on the proposed model. Our numerical results show that the proposed FD–HD transmission and channel acquisition approach outperforms its conventional HD counterpart and achieves higher data rates. [ABSTRACT FROM AUTHOR]

Communications over power lines in the frequency range above 2 MHz, commonly referred to as broadband (BB) power line communications (PLC), has been the focus of increasing research attention and standardization efforts in recent years. BB-PLC channels are characterized by a dominant colored non-Gaussian additive noise, as well as by periodic variations of the channel impulse response and of the noise statistics. In this paper, we study the fundamental rate limits for BB-PLC channels by bounding their capacity while accounting for the unique properties of these channels. We obtain explicit expressions for the derived bounds for several BB-PLC noise models, and illustrate the resulting fundamental limits in a numerical analysis. [ABSTRACT FROM AUTHOR]

The characteristic basis function method (CBFM) was developed as an algorithm to accelerate the analysis based on direct matrix solver. In CBFM, the optimum block size greatly influences the overall analysis time. In this paper, we propose a guideline for setting the optimal block size that can be applied to every algorithm based on CBFM. Rough estimation of the optimal block size is $L_{B}^{rough} \approx 0.05 N^{6/{29}}$ , and the exact optimal block size can be determined through preprocessing based on rough estimation. Numerical results of electromagnetic scattering problems are shown to demonstrate the performance of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, we apply for the first time the nonlinear-embedding technique to the design of power amplifiers (PAs) based on laterally-diffused metal-oxide-semiconductor (LDMOS) field-effect transistors. Such a design technique is based on setting the transistor load line at the intrinsic current-generator plane, according to well-known theoretical guidelines. Then, the selected operating condition can be transposed at any design frequency at the extrinsic transistor terminals, by means of a model of the device nonidealities, such as the nonlinear intrinsic capacitances and the linear parasitic effects. A harmonically-tuned high-efficiency class-F and a wideband class-AB PAs operating within the FM broadcasting band 88 ÷ 108 MHz based on a 10-W LDMOS are then designed and realized. To definitely assess the validity of the proposed approach for the LDMOS technology, we compare the measured performance on the fabricated PAs with the expected predictions. [ABSTRACT FROM AUTHOR]

Millimeter wave (mmWave) communications is a promising approach to satisfy the increasing high data rate requirement of next generation mobile communications. This paper studies the downlink coverage performance of mmWave cellular networks with imperfect beam alignment. An enhanced antenna model is adopted to model the directional antenna beamforming pattern, in which the mainlobe beamwidth and directivity gain can be expressed as functions of the number of elements in the antenna array. After deriving the probability density function of the distance between mobile station and its serving base station (BS), the directivity gain with imperfect beam alignment is obtained as a discrete random variable. Then, a computationally tractable expression is obtained for the coverage probability of mmWave cellular networks. This generalized expression can be applied in different blockage regimes, e.g., general blockage regime, full-blockage regime, and nonblockage regime with or without beam alignment errors. Numerical results show that small beam alignment errors will not deteriorate the coverage performance significantly, and the antenna array with the less number of elements provides higher robustness against the beam alignment errors. Moreover, when the beam alignment error is small enough, the coverage performance can be improved by increasing the BS intensity and the number of elements in the antenna array. [ABSTRACT FROM AUTHOR]

Testing and debugging of electrostatic discharge (ESD) or electrical fast transient issues in modern electronic systems can be challenging. The following paper describes the design of an on-chip circuit that detects and stores the occurrence of a fast transient stress event at the ESD protection structures in an input/output pad. Measurements and simulations of a test chip in 90 nm technology show that this circuit can accurately detect and record the presence of a transient stress event with a peak current as low as 0.9 A or a duration as short as 1 ns, and that the detector works well across typical temperature and process variations. The small size of the detector allows it to be used effectively in lowcost commercial integrated circuits. The detector was tested in a system-level environment and successfully records transient events. The importance of simulating with intelligent approximations of the system parasitics is described and demonstrated in measurements. An improved detector is discussed, which performs better in terms of process variations. [ABSTRACT FROM AUTHOR]

This paper proposes a new network-on-chip (NoC)-reused test access mechanism (TAM) for testing multiple identical cores. It can test multiple cores concurrently and identify faulty cores to derate the chip by excluding the core. In order to minimize the test time, the TAM utilizes the majority value of test response data. All of the cores can thereby be tested in parallel and test costs (in both test pins and test time) are exactly the same as those for a single core. The hardware overhead is minimized by reusing the NoC infrastructures and transfer-counters are designed as a majority analyzer. The experimental results in this paper show that the proposed TAM can test multiple cores in the same time as a single core and with negligible hardware overhead. [ABSTRACT FROM PUBLISHER]

The virtual impedance concept is increasingly used for the control of power electronic systems. Generally, the virtual impedance loop can either be embedded as an additional degree of freedom for active stabilization and disturbance rejection, or be employed as a command reference generator for the converters to provide ancillary services. This paper presents an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters. The control output impedance shaping attained by the virtual impedances is generalized first using the impedance-based models. Different virtual impedances and their implementation issues are then discussed. A number of practical examples are demonstrated to illustrate the feasibility of virtual impedances. Emerging applications and future trends of virtual impedances in power electronic systems conclude this paper. [ABSTRACT FROM AUTHOR]

This paper describes the sensitivity analysis concerning time-to-go estimation error for the class of optimal impact angle control guidance laws under a stationary or a slowly moving target. First, in this paper, the closed-form solutions of those guidance laws for a lag-free system are determined. Then, we derive the explicit expressions of the terminal errors (i.e., miss distance and impact angle error) in the presence of a constant positive time-to-go estimation error. Based on these results, the guidance parameters that can help reduce the sensitivity to time-to-go estimation error are identified. Additionally, the terminal performance of the presented optimal impact angle guidance laws is evaluated from the standpoint of robustness against the time-to-go estimation errors. Numbers of linear homing simulations are also performed to confirm the analysis results. [ABSTRACT FROM AUTHOR]

Detection of small changes in natural formations and human-made constructions is a promising application of synthetic aperture radar (SAR). This paper deals with a specific radar, which is a ground-based SAR using noise waveform. Being fully coherent, SAR provides both phase and amplitude information for every pixel in the mapped area. This gives rise to the possibility of comparing phases between the images taken from the same position at different times in order to extract information about the changes that have occurred between subsequent radar measurements. Such a technique, called coherent change detection (CCD), allows changes of a subwavelength size to be detected. The use of a noise waveform for sounding ensures high electromagnetic compatibility and interference immunity. Moreover, it enables long integration time in the detection stage. However, the random nature of probing signals used in noise radars leads to randomness of the output signals and the preservation of residual fluctuation in the images generated. This random residual, along with external noise, influences the overall accuracy of the phase measurement in noise radar. In this paper, the theoretical and experimental investigation of this specific influence of noise on the precision of phase measurements is presented. The theoretical part of the paper is focused on the estimation of the Cramer-Rao lower bound for the phase measurements using both statistical theory and geometrical interpretation of complex signals. In the experimental part, these findings are verified with dedicated measurements of a metallic sphere displacement, carried out with the help of a ground-based noise waveform SAR. [ABSTRACT FROM AUTHOR]

To integrate a software component into a system, it must interact properly with the system's other components. Unfortunately, the decisions about how a component is to interact with other components are typically committed long before the moment of integration and are difficult to change. This paper introduces the Flexible Packaging method, which allows a component developer to defer some decisions about component interaction until system integration time. The method divides the component's source into two pieces: the ware, which encapsulates the component's functionality; and the packager, which encapsulates the details of interaction. Both the ware and the packager are Independently reusable. A ware, as a reusable part, allows a given piece of functionality to be employed in systems in different architectural styles. A packager, as a reusable part, encapsulates conformance to a component standard, like an ActiveX control or an ODBC database accessor. Because the packager's source code is often formulaic, a tool is provided to generate the packager's source from a high-level description of the intended interaction, a description written in the architectural description language UniCon. The method and tools are evaluated with a series of experiments in which three wares and nine types of packaging are combined to form thirteen components. [ABSTRACT FROM AUTHOR]

This paper demonstrates the implementation of indoor Bluetooth communication multi-hop networks. Since the performance of such networks determines the range of applications that they can support, the performance of Bluetooth wireless multi-hop networks is a common topic of interest. Communication network models are widely used to estimate the performance of networks in many different aspects. This paper focuses on one of the aspects, i.e., the time performance of the data transportation network of a Bluetooth multi-hop home network, and provides a novel empirical model for latency in multi-hop networks with asynchronous links when links are active. The model offers a sharp estimation of the latency added with every hop in the communication such that electronics product designers and network managers can effectively run time-constrained applications in this type of network. The model is based on the results from experiments carried out on a real test bed. The test bed includes Bluetooth nodes and proprietary middleware at the HCI (Host Controller Interface) level of communication. The experimental results show that the time performance worsens with an increasing number of hops in the communication and additionally provide evidence of the quadratic dependence on the number of hops exhibited by the latency 1. [ABSTRACT FROM AUTHOR]

Space-time adaptive processing (STAP) is a family of algorithms frequently employed in surface moving target indication radar systems to enable detection of moving objects in the presence of fixed (i.e., nonmoving) clutter. In this paper, two new closed-form expressions that quantify the loss associated with the STAP notch centered on clutter are derived in terms of system parameters of interest. Although there are many excellent reports, books, and papers focused on STAP, a simple yet accurate approximation for the STAP notch has not previously appeared. It is also shown that a new, accurate approximation for the important STAP metric known as minimum detectable velocity may be derived from the STAP notch expression. Furthermore, accurate expressions are derived that predict when ?aperture-limited? STAP performance may be obtained. This work provides the first analytical, unifying connection between these STAP metrics. As they are implemented in compact closed-form expressions, the new results are attractive for system design. The significant computational benefits associated with the new results can be very advantageous in trade studies or large simulations in which STAP performance estimates must be computed thousands of times. It is expected that this work will be of great use to both readers with a background in STAP and readers new to this field. For readers with STAP experience, this work provides a new understanding of the drivers of STAP performance and of the interconnections between STAP performance measures. For readers new to the STAP field, this work removes the mystery associated with STAP by providing intuition into how STAP works. With accurate, analytical expressions, system engineers can now implement accurate predictions of STAP performance without the necessity of constructing patch-based analysis tools that estimate STAP performance by computing the notch associated with hundreds to thousands of clutter patches. [ABSTRACT FROM AUTHOR]

This paper presents a novel system that allows elevating large structures by using a set of lifting towers that, adequately controlled with a synchronized operation, succeed in pulling the spatial mesh up to the height where it should stay. By doing so, the mounting of the spatial mesh can be carried out on the ground in an easier and, most important of all, safer way; it also gives rise to a shorter final time and, thereby, a cost reduction. This paper deals with the elevation system designed to pull the mesh up and specifically focuses on the electronic system that allows controlling their movement. Comments about the overall control that coordinates the operation of all of the mechanical structures involved are also provided. [ABSTRACT FROM AUTHOR]

This paper presents a two-stage approach to handle fixed-outline floorplanning for mixed size modules, named F-FM. F-FM combines the advantages of the analytical approach and the slicing tree representation. Thus, it is not only suitable for handling fixed-outline floorplanning but also can be extended to handle other important issues in floorplanning such as routability or thermal effect in addition to wirelength. Recently, low power has become big challenges in very large-scale integration designs, which makes voltage-island driven floorplanning more important than ever. Although the problem has been discussed by previous works, no paper considers signal wirelength, powerplanning, and voltage drop at the same time under the fixed-outline constraint. Thus, this paper extends F-FM to handle this problem and consider these issues by properly dividing modules in a voltage domain into several islands. The experimental results show our approach obtains the best results in these problems. [ABSTRACT FROM AUTHOR]

This paper proposes a new scheme to secure the transmissions in an untrusted decode-and-forward (DF) relaying network. A legitimate source node, Alice, sends her data to a legitimate destination node, Bob, with the aid of an untrusted DF relay node, Charlie. To secure the transmissions from Charlie during relaying time slots, each data codeword is secured using a secret-key codeword that has been previously shared between Alice and Bob during the perfectly secured time slots (i.e., when the channel secrecy rate is positive). The secret-key bits exchanged between Alice and Bob are stored in a finite-length buffer and are used to secure data transmission whenever needed. We model the secret-key buffer as a queueing system and analyze its Markov chain. Our numerical results show the gains of our proposed scheme relative to benchmarks. Moreover, the proposed scheme achieves an upper bound on the secure throughput. [ABSTRACT FROM AUTHOR]

The amount of electronic systems in agriculture machinery grows, becoming more complex and multifunctional. Due to the increasing number of devices connected to the network and the complexity of their functions, the current controller area network (CAN) becomes overloaded and CAN with flexible data rate (CAN FD) emerges as an alternative. This paper presents the simulation of an agriculture machine vehicular network using the higher layer protocols J1939 and ISO11783 (ISOBUS) and the performance comparison of the network using CAN, CAN FD 8 B and CAN FD 64 B. The presented contribution is mainly twofold: the proposal of an SAE J1939/ISOBUS compliant CAN FD 64 B model for a highly demanding vehicular network, and a detailed analysis of the real-time properties of this model compared to CAN and CAN FD 8 B. In the performed experiments, on the network permanent regime, periodic messages of machine control functions and network management data were sent by the devices connected to the network. The bus load usage, the response time, and jitter of these messages were analyzed to evaluate the real-time characteristics of the network. Compared to CAN, CAN FD had faster object pool transference, lower bus load usage, shorter worst case response time, and lower jitter. [ABSTRACT FROM PUBLISHER]

The ball grid array (BGA) structure is the interconnection between package to printed circuit board and the discontinuity from BGA affects the performance for the whole link path in the high-speed digital system. So, it is important to accurately model the BGA structures. In current methods, the current distribution of conductors is treated as isotropic. However, the pitch size of solder balls is comparable to the diameter. The current is no longer uniformly distributed. In this paper, a fast modal-based approach is developed to accurately and efficiently capture the proximity effect. Image theory is also applied in the proposed approach to reduce the computational domain from 3-D structure to 2-D. The matrix reduction approach is applied to obtain the physical loop inductance. The lumped capacitance is obtained in [1]. A $\pi $ topology equivalent circuit model for the BGA structure is built. Good agreement between the equivalent circuit model and full-wave simulation can be achieved up to 40 GHz. [ABSTRACT FROM AUTHOR]

New topologies of electric car use high power switching devices which must be integrated with a growing range of electronic systems in small places. A good performance of the car relies on the electromagnetic compatibility among these systems, which requires the characterization of the noise and interferences present in the system. To characterize the noise, both emission and susceptibility issues as well as coupling mechanisms must be studied. This paper presents the work performed for the electromagnetic mapping of a four-wheel fully electric car, which involves both simulation and experimental measurements. It has been carried out within the E-VECTOORC project (FP7-INFSO-284708), in collaboration with car manufacturers such as Jaguar Land Rover and Škoda. [ABSTRACT FROM AUTHOR]

Car manufacturers have to size electric and electronic systems to avoid the risk of short circuits while, at the same time, ensuring a viable economic balance. In other words, the copper mass must be sufficient for safety reasons but not excessive for cost reasons. It is, thus, necessary to monitor the critical points of the electric architecture in order to make an appropriate decision to maintain a high level of safety. However, due to physical and economic constraints, direct temperature measurement of these critical points is seldom possible. Moreover, temperature monitoring at these points would not allow one to determine whether the rise in temperature was related to degradation of the contact or whether it was due to the generation of thermal power by another component. The objective of this paper is, thus, to propose a new method to monitor critical points of the electric architecture that does not require direct measurements. In order to achieve this objective, an electrothermal model of the architecture was developed, and a diagnosis method was used. The method was applied to detect abnormal variations in the contact resistance inside a connector, which is a critical point commonly encountered in the electrothermal chain of automotive vehicles. The efficiency of the algorithm was evaluated on a dedicated test bench. The proposed approach is able to detect a deviation of about 10% in the contact resistance, thus validating the proposed methodology. [ABSTRACT FROM AUTHOR]

In this paper, a 1.1-μm-pitch 33-Mpixel 240-fps backside-illuminated 3-D-stacked CMOS image sensor with three-stage cyclic-cyclic-successive-approximation-register (SAR) analog-to-digital converters (ADCs) is developed. The narrow-pitch interconnection technology that connects the pixels and arrayed ADCs inside the pixel area is described. The 3-D-stacked architecture, constructed using the interconnection technology, makes it possible to place a 1932 (H) × 4 (V) correlated-double-sampling/ADC array underneath the pixel area. Furthermore, the pipelined and parallel operation of the three-stage cyclic-cyclic-SAR ADC architecture effectively reduces the conversion time period and power consumption and achieves 12-b precision within one horizontal scan time of 0.92 μs. As a result, the interconnection technology and ADC architecture achieved a high frame rate of 240 fps in 33 Mpixels. Random noise of 3.6 e- and low power consumption of 3.0 W were attained at an extremely high pixel rate of 7.96 Gpixel/s. A good figure of merit is achieved compared with recently developed image sensors. [ABSTRACT FROM AUTHOR]

Radar tracking of aircraft targets at low elevation angles can be complicated by clutter from wind turbines, which we define to be clutter. In this paper, we study detection in a staring pulse-Doppler radar. By exploiting the second-order correlation structure of this wind-turbine clutter we derive a target detector that uses a sequence of adaptive coherence scores. The detector uses a multipulse coherence statistic consisting of an incoherent geometric average of coherently computed adaptive coherence scores. The detector compares favorably to a multipulse coherence detector that uses no modeling or estimation of the clutter. [ABSTRACT FROM PUBLISHER]

The paper proposes a cooperative scheme for the coexistence of a multiple-input-multiple-output (MIMO) communication system and a matrix completion (MC) based, collocated MIMO (MIMO-MC) radar. To facilitate the coexistence, and also deal with clutter, both the radar and the communication systems use transmit precoding. For waveform flexibility, the radar uses a random unitary waveform matrix. We prove that for such waveforms and any precoding matrix, the error performance of MC is guaranteed. The radar transmit precoder, the radar subsampling scheme, and the communication transmit covariance matrix are jointly designed in order to maximize the radar SINR, while meeting certain communication rate and power constraints. The joint design is implemented at a control center, which is a node with whom both systems share physical layer information, and which also performs data fusion for the radar. We provide efficient algorithms for the proposed optimization problem, along with insight on the feasibility and properties of the proposed design. Simulation results show that the proposed scheme significantly improves the spectrum sharing performance in various scenarios. [ABSTRACT FROM AUTHOR]

The characterization of the performance of wireless devices plays a significant role in developing radio products that meet the demands of the latest standards and deliver a satisfying user experience. With current standard total isotropic sensitivity (TIS) measurement, the transmitters are set to work at their maximum transmission power level. However, the standard TIS test procedure is unable to accurately reflect a receiver's performance because in actual usage transmitters are rarely working at their maximum power level. In measurements, different kinds of devices hold different maximum power levels. The measured radio sensitivity depends on the instantaneous local temperature of the radio, and the local temperature depends on the heat generation (power levels), the heat dissipation, and time. So the power levels and the thermal conditions could affect their radio sensitivity and, hence, the TIS. With standard TIS methods, the maximum power level and the radio's thermal condition cause ambiguity in the measurements. However, this paper proposes a new objective TIS method. With this new TIS method, the measured TIS is a function of the transmitter power level at its thermally stable condition. The proposed method resolves the ambiguity of the TIS measurement. [ABSTRACT FROM PUBLISHER]

In partial label learning, each training example is associated with a set of candidate labels among which only one is the ground-truth label. The common strategy to induce predictive model is trying to disambiguate the candidate label set, i.e., differentiating the modeling outputs of individual candidate labels. Specifically, disambiguation by differentiation can be conducted either by identifying the ground-truth label iteratively or by treating each candidate label equally. Nonetheless, the disambiguation strategy is prone to be misled by the false positive labels co-occurring with ground-truth label. In this paper, a new partial label learning strategy is studied which refrains from conducting disambiguation. Specifically, by adapting error-correcting output codes (ECOC), a simple yet effective approach named Pl-ecoc is proposed by utilizing candidate label set as an entirety. During training phase, to build binary classifier w.r.t. each column coding, any partially labeled example will be regarded as a positive or negative training example only if its candidate label set entirely falls into the coding dichotomy. During testing phase, class label for the unseen instance is determined via loss-based decoding which considers binary classifiers’ empirical performance and predictive margin. Extensive experiments show that Pl-ecoc performs favorably against state-of-the-art partial label learning approaches. [ABSTRACT FROM PUBLISHER]

Context: Variability (i.e., the ability of software systems or artifacts to be adjusted for different contexts) became a key property of many systems. Objective: We analyze existing research on variability in software systems. We investigate variability handling in major software engineering phases (e.g., requirements engineering, architecting). Method: We performed a systematic literature review. A manual search covered 13 premium software engineering journals and 18 premium conferences, resulting in 15,430 papers searched and 196 papers considered for analysis. To improve reliability and to increase reproducibility, we complemented the manual search with a targeted automated search. Results: Software quality attributes have not received much attention in the context of variability. Variability is studied in all software engineering phases, but testing is underrepresented. Data to motivate the applicability of current approaches are often insufficient; research designs are vaguely described. Conclusions: Based on our findings we propose dimensions of variability in software engineering. This empirically grounded classification provides a step towards a unifying, integrated perspective of variability in software systems, spanning across disparate or loosely coupled research themes in the software engineering community. Finally, we provide recommendations to bridge the gap between research and practice and point to opportunities for future research. [ABSTRACT FROM PUBLISHER]

Energy harvesting has become a popular source for low-power electronic systems such as wireless sensors and biomedical implants. Energy can be extracted from a number of ambient conditions such as vibration, solar, and thermal gradient. Just like renewable sources, the associated switching power converters can be controlled to harvest maximum power from these miniature systems. However, conventional schemes, such as a conventional maximum power point tracking (MPPT) controller for solar cells, are complex and cannot be utilized in low-power energy systems due to their cost and power requirements. In this paper, a novel optimum energy harvesting scheme is proposed, which controls the duty cycle of the converter to maximize the output power of the system. The control system employs only simple mixed-signal components and can be applied to low-power systems. The proposed scheme does not depend on the characteristics of a specific source and is applicable for different energy systems. In this paper, it is utilized to achieve optimized energy harvesting for two completely different fixed excitation systems, namely, a low-voltage vibration-based electromagnetic microgenerator and a miniature solar cell array. Both simulation and experimental results are provided to validate the proposed scheme. [ABSTRACT FROM PUBLISHER]

Thin integrated passive devices (IPDs) will play a critical role in the miniaturization of future high-performance electronic and bioelectronic systems. Silicon-based capacitors are currently manufactured with expensive processes such as sputtering and atomic layer deposition. Solution-deposited electrodes and dielectrics in trench and through-via structures provide alternative low-cost routes. Two solution-deposition techniques, spin-coating and vacuum infiltration, are investigated in this paper. A representative all-solution-derived thin-film capacitor consisting of sol–gel lanthanum nickel oxide (LNO) as the electrode, and sol–gel lead zirconate titanate as the dielectric thin-film is demonstrated in the first part of this paper. The role of barriers in reducing leakage currents is studied using three electrode systems: LNO/Si, LNO/ZrO2/Si, and LNO/Pt/Ta/Si. Capacitors with LNO electrodes directly deposited on naturally oxidized silicon resulted in higher leakages, more defects and a lower yield. The results show that the zirconia barrier suppresses the leakage current in the dielectric. The second part of this paper describes sol–gel films deposited in the through-via and trench surfaces to demonstrate the sol–gel conformal coating technique. Scanning electron microscopy cross-section analysis shows that the vacuum infiltration conformally coated through-vias. These solution deposition techniques may have the potential to fabricate IPD capacitors at low cost. [ABSTRACT FROM AUTHOR]

Nowadays, the interest on the development of orbiting radar sounders for the observation of Earth polar areas is increasing. In this context, the analysis of the structure of the ice stratigraphy is of primary importance for the study of the past history and for the prediction of the evolution of icy environments. However, as proven by planetary missions, orbiting radar sounders provide a huge amount of data. Thus, the development of automatic techniques for the analysis of these data is of fundamental importance for proper data exploitation. In this paper, we propose a novel method for the automatic detection of subsurface linear features from radar sounder data acquired in icy regions showing extended layering. The proposed method allows the estimation of the position of the linear features with subpixel accuracy. Moreover, each detected linear interface is treated as a single object which is completely described by the position of its points, the estimated local width, and the contrast. This allows the direct measurement of geometrical and radiometric parameters (e.g., slope angle and intensity) without the need of further postprocessing steps. This paper also proposes some measurements for deriving from the output of the proposed technique important variables that can characterize quantitatively the properties of the detected linear features (e.g., mean depth and mean intensity) and their distribution (e.g., number and density of layers). The effectiveness of the proposed method is confirmed by the results obtained on several radargrams acquired by the Shallow Radar on the North Pole of Mars. [ABSTRACT FROM PUBLISHER]

Planar electromagnetic interference (EMI) filter has good application prospect in power electronics system with the advantages of small volume and good high-frequency performance. However, a complete theoretical system for the design of planar EMI filter has not been proposed yet. In this paper, an integrated structure formed by an annular “inductor–capacitor” (LC unit) is proposed first, which can be used as the basic cell of the planar EMI filter. A general arc transmission theory is also proposed, based on which the distributed-parameter model of the LC unit is established. Then, this LC unit can be equivalent to the two-port network by employing the model transformation method. Besides, the turn-to-turn electromagnetic parameter is extracted using finite element method, which provides the foundation for the research of LC unit and electromagnetic performance of the filter. The design method and the implementation of the whole planar EMI filter are elaborated in details, and the empirical initial values of the related structural sizes are also presented in this paper. In order to verify the proposed design theory, several EMI filters formed by LC units are designed according to the specifications. Common-mode insertion losses of the EMI filter are calculated and measured, respectively. The results verify the feasibility of the design theory. [ABSTRACT FROM AUTHOR]

In a WLAN setting, the system throughput may be heavily affected by a small number of low data rate clients due to the packet-fairness property provided by IEEE 802.11 DCF. This is regarded as the performance anomaly problem. Client relay is a technology widely adopted to solve this problem. An important issue of client relay is to decide when a client's traffic should be relayed and who relays it. However, the existing protocols fail to consider the overhead introduced by DCF contentions, resulting in an inaccurate performance analysis and lead to wrong decisions for client relay. In this paper, we focus on the performance analysis for multi-hop relay networks with consideration of contention overhead of relay nodes in IEEE 802.11 DCF protocols. The main work of this paper includes: 1) we consider the contention overhead in the performance analytical model of collaborative relay networks. This model is more accurate than the existing models. 2) We present a throughput analytical model that considers different traffic demands of clients for the traffic pattern of relay networks. Extensive simulations have been done in NS-2. The simulation results show that our algorithm is more accurate and achieves higher relay performance, compared with existing methods. [ABSTRACT FROM PUBLISHER]

In this paper, we consider network coded (NCed) Hybrid-ARQ (HARQ) for multiple unicast flows. The main contribution of the paper is the derivation of throughput expressions for NCed HARQ with arbitrary number of users in identical i.i.d. channels amid packets for all users. We apply the result to Rayleigh fading channels and two packet combining schemes: incremental redundancy (IR) and chase combining (CC). We verify the analytical results with simulations and observe substantial SNR improvements over NCed ARQ and HARQ. The SNR gains in the moderate/high and low throughput regimes are mainly due to network coding and packet combining, respectively. For low/moderate SNRs, NCed HARQ with IR surpasses the CC performance. In addition, we introduce a novel re-transmission strategy that makes the network coding more efficient at low SNR. [ABSTRACT FROM PUBLISHER]

Microelectronic circuits exhibit increasing variations in performance, power consumption, and reliability parameters across the manufactured parts and across use of these parts over time in the field. These variations have led to increasing use of overdesign and guardbands in design and test to ensure yield and reliability with respect to a rigid set of datasheet specifications. This paper explores the possibility of constructing computing machines that purposely expose hardware variations to various layers of the system stack including software. This leads to the vision of underdesigned hardware that utilizes a software stack that opportunistically adapts to a sensed or modeled hardware. The envisioned underdesigned and opportunistic computing (UnO) machines face a number of challenges related to the sensing infrastructure and software interfaces that can effectively utilize the sensory data. In this paper, we outline specific sensing mechanisms that we have developed and their potential use in building UnO machines. [ABSTRACT FROM AUTHOR]

This paper proposes a methodology to identify and protect vulnerable components of connected gas and electric infrastructures from malicious attacks, and to guarantee a resilient operation by deploying valid corrective actions, while accounting for the interdependence of the gas pipeline network and power transmission network. The proposed mathematical formulation gives rise to to a trilevel optimization problem, where the lower level is a multiperiod economic dispatch of the gas–electric system and seeks operating strategies under available resources and given attack, the middle level distinguishes the most threatening attack on the coupled physical infrastructures, and the upper level provides optimal preventive decisions to reinforce the vulnerable components and increase the system resilience. By reformulating the lower level problem as a mixed integer linear programming, a nested column-and-constraint generation algorithm is developed to solve the min–max–min model. Case studies on two test systems demonstrate the effectiveness and efficiency of the proposed methodology. [ABSTRACT FROM AUTHOR]

The dynamic range of frequency modulated continuous wave (FMCW) radar sensors is often limited by the phase noise of the ramp signal. Especially at millimeter wave (mm-wave) frequencies, a low phase noise signal is very difficult to obtain. In this paper, a new system architecture, which is implemented in a low-cost, ultracompact FMCW radar monolithic microwave integrated circuit (MMIC) at 160 GHz, is proposed to address this topic. The approach is based on a frequency offset synthesizer, whose upconverting mixer is driven by a stabilized low phase noise local oscillator (LO) signal. This LO is generated by a fixed-frequency phase locked loop with a 2^N divider. The upconversion of the ramp signal with the stabilized LO signal leads to an excellent mm-wave phase noise of −89 dBc/Hz at a frequency offset of 1 MHz. By integrating the antennas on the MMIC, interconnects at mm-wave frequencies to package or printed circuit board are avoided and a simple assembly and interconnection technology is feasible. The ultracompact MMIC is realized on an area of only 2 mm2, including the integrated antennas. A precision below 5 \mu \textm for range measurements is demonstrated with the radar sensor. Additionally, the radar performance is evaluated with two different voltage-controlled oscillators for the generation of the ramp signal. [ABSTRACT FROM AUTHOR]

This paper presents a novel development of lower limb exoskeleton, which is named as CASWELL, and its repetitive learning control design for movement assistance. CASWELL has five degrees of freedom per leg, two of which are driven by linear single-rod electrohydraulic actuators. First, the mechanical structure and embedded electronic system are constructed, respectively. Second, by incorporating the systems of rigid body and electrohydraulic actuators, the complete dynamics of CASWELL are analyzed and modeled. Third, under the framework of backstepping design, a repetitive learning control scheme is presented to address the periodic tracking control of lower limbs of exoskeleton, where the learning convergence of the closed-loop system is proved rigorously in a Lyapunov way. Finally, the proposed controller is implemented in the embedded electronic system via a 32-bit microcontroller, and tested on the developed CASWELL. The experimental results are given to demonstrate the performance of the whole exoskeleton system. [ABSTRACT FROM AUTHOR]

In frequency-modulation (FM)-based passive radar, the strong side peaks randomly appearing in the ambiguity function will generate a false alarm of target detection. To mitigate this side peak interference, this paper starts with a detailed analysis of the structure and ambiguity function of FM stereo signal. Then, it expounds the formation and characteristics of side peaks, together with a side peak identification method, which identifies and discards the false detections of the same range and Doppler caused by side peaks, respectively. The performance analysis, conducted using both simulated data and real recorded datasets, proves that the proposed method can eliminate the false targets caused by side peaks thus improving the detection performance in FM-passive radar. [ABSTRACT FROM PUBLISHER]

Reverse engineering (RE) of electronic systems is performed for many different reasons, including, but not limited to, failure analysis and fault isolation, obsolescence management, proof of IP rights infringement, security assessment, development of attacks, and counterfeiting. Regardless of the goal, it is imperative that the community understands the requirements, complexities, and limitations of RE. Traditional RE is based on a destructive process of serial sectioning followed by imaging, which is time-consuming, expensive, and error-prone. However, with the advent of advanced characterization tools and imaging software, this is starting to change. In this paper, we introduce a nondestructive approach for printed circuit board (PCB) RE based on X-ray tomography. The imaging parameters for a successful tomography are explained in detail and combined with advanced 3-D image processing and analysis to automate RE, thereby lowering the associated time and cost. We demonstrate our proposed process on two PCBs, a four-layer custom designed board, and a more complex commercial board. Lessons learned from this effort can be used to both develop advanced countermeasures and establish a more efficient workflow for instances where RE is unavoidable. [ABSTRACT FROM AUTHOR]

This paper reports on the optimization of a 36 V complimentary bipolar design by using a new depletion mode field-effect architecture for the collector of the bipolar that greatly expands the boundary of the familiar tradeoffs. This achieves an n-p-n with a measured \vert \beta at 1 V \times V_{a} at 18 \text{V}\vert = \vert 270\times1100\,\,\text{V}\vert , a JfT at 1 V = 28.7\,\,\mu \textA\mu \textm^\mathrm \mathbf -2 , and \vert fT at 1 V \times BV \vert = \vert 2.6 GHz \times58\,\,\textV\vert , with a p-n-p having a \vert \beta at 1 V \times V_{a} at 18 \text{V}\vert = \vert 250\times800\,\,\text{V}\vert , a JfT at 1 V = 27.0\,\,\mu \,\,\textA\mu \textm^\mathrm \mathbf -2 , and \vert fT at 1 V \times BV \vert = \vert 1.9 GHz \times69\,\,\textV\vert . While these performance enhancements appear to offer a lot with little expense, they do serve to reveal an additional tradeoff between \beta \times Va \times fT \times BV \times JfT and Linearity. This is where the curvature of the forward output characteristic curves quantified by the extrapolated Early voltage significantly changes over the voltage range \vert 0 –10 . Through the use of measured silicon results with calibrated TCAD simulations, the physics behind this depletion mode collector design is explained, and using this understanding, it ultimately shows how it is possible to limit the range of the associated nonlinear performance for low collector biases. Then, keeping linearity as a key performance target together with the field-effect architecture, the 36 V bipolar is rebalanced to achieve an n-p-n with a \vert \beta at 1 V \times Va at 18 V \times fT at 1 V $\times $ JfT at 1 V \times $ BV \times $ Linearity \vert = \vert 270 \times 220$ V \times2.6 V \times $ (0.2–30 V) Linearity \vert $ , and a p-n-p with a \vert \beta \times $ fT at 1 V \times $ JfT at 1 V \times $ BV \times $ Linearity \vert = \vert 185\times180$ V V $\times $ (0.2–30 V) Linearity $\vert $ . [ABSTRACT FROM AUTHOR]

Reuse methodologies are now widely used to design digital circuits. They are based on the concept of intellectual property (IP), or virtual block of computing, characterized by a behavioral model, synthesizable or not. The design reuse for analog integrated systems is much less natural and less standardized. This paper addresses the issue of an analog design flow based on reuse, focusing on three key issues: the formal content of the IP block, the design of a reusable analog IP, and the organization of a design flow centered on an IP library. After a conceptual overview, this paper presents the methodological principles and details examples with a tutorial intention. The objective is to guide the designer involved in the process of developing analog IPs and corresponding design flow. This method is inspired by platform-based design and adapted here on an original case study: the design of full-custom neuromimetic integrated circuits, built from specific analog computational blocks. The development of reusable IPs represents an additional effort, mainly for behavioral modeling and characterization. Nevertheless, the steps illustrated in this case study show that the extra time provides a definite advantage to future design projects. [ABSTRACT FROM AUTHOR]

Failures in electronics subjected to shock and vibration are typically diagnosed using the built-in self test (BIST) or using continuity monitoring of daisy-chained packages. The BIST, which is extensively used for diagnostics or identification of failure, is focused on reactive failure detection and provides limited insight into reliability and residual life. In this paper, a new technique has been developed for health monitoring and failure mode classification based on measured damage precursors. A feature extraction technique in the joint-time-frequency analysis (JTFA) domain has been developed along with pattern classifiers for fault diagnosis of electronics at the product level. The Karhunen Loéve transform (KLT) has been used for feature reduction and de-correlation of the feature vectors for fault-mode classification in electronic assemblies. Euclidean, and Mahalanobis, and Bayesian distance classifiers based on JTFA, have been used for classification of the resulting feature space. Previously, the authors have developed damage precursors based on time and spectral techniques for health monitoring of electronics without reliance on continuity data from daisy-chained packages. Statistical pattern recognition techniques based on wavelet packet energy decomposition have been studied by authors for quantification of shock damage in electronic assemblies and auto-regressive moving average; time-frequency techniques have been investigated for system identification, condition monitoring, and fault detection and diagnosis in electronic systems. However, identification of specific failure modes is not possible. In this paper, various fault modes, such as solder interconnect failure, interconnect missing, chip delamination, chip cracking etc., in various packaging architectures have been classified using clustering of feature vectors based on the KLT approach. The KLT de-correlates the feature space and identifies dominant directions to describe the space, eliminating directions that encode little useful information about the features. The clustered damage precursors have been correlated with underlying damage. Several chip-scale packages have been studied with lead-free second-level interconnects, including SAC105, SAC305 alloys. Transient strain has been measured during the drop event using digital image correlation and high-speed cameras operating at 100 000 frames/s. Continuity has been monitored simultaneously for failure identification. Fault-mode classification has been done using KLT and JTFA analysis of the experimental data. In addition, explicit finite element models have been developed, and various kinds of failure modes have been simulated, such as solder ball cracking, trace fracture, package falloff, and solder ball failure. Models using cohesive elements present at the solder joint-copper pad interface at both the printed circuit board and package side have also been created to study the traction-separation behavior of solder. Fault modes predicted by simulation-based precursors have been correlated with those from experimental data. [ABSTRACT FROM PUBLISHER]

The framework for this paper is the growing concern about the worldwide increasing energy consumption of telecommunications systems and data centers, and particularly the contribution of the thermal management system. The present energy usage of these systems is discussed, as well as the relationship between cooling system design and the total cost of ownership. This paper identifies immediate and future thermal bottlenecks facing the industry, ranging from technological issues at the component and system level to more general needs involving reliability, modularity, and multidisciplinary design. Based on this enumeration, the main challenges to implementing cooling solutions are reviewed. Particular attention is paid to implementing liquid cooling, since this technology seems the most promising to addressing the key thermal bottlenecks, and improving the future sustainability of thermal management in the telecom and data center industry. Finally, an outlook is presented toward future potential challenges. [ABSTRACT FROM PUBLISHER]

In high-precision detector systems, the power supply usually need to be ultra-low noise and stabilized. Design and implementation of an ultra-low noise power supply is described in this paper. We implemented and tested the power system actually in a scientific CCD (Charge-coupled device) detector system, but the design structure could be used in many high-precision detector systems as infrared detector or high-energy particles detectors. The power system uses DC-DC switching regulators and LDO regulators for power generating, uses multi-stage filters for noise reducing. Multi-output power supply with noise about 40~\mu \text V\mathbf {rms} is achieved, the overall energy efficiency is 68.5%. Besides, the electronic system takes the low temperature as an important consideration, and the system has been tested in an extreme environment as low as 193 K. [ABSTRACT FROM AUTHOR]

In a typical radar system, the same hypothesis testing problem is periodically repeated to constantly monitor the scene: this results in a fundamental tradeoff between integration time and scan rate. In this paper, we propose a novel design criterion for radar systems, which carefully balances the contrasting requirements for a large probability of detection, a small probability of false alarm, and a short scan time. In particular, our goal is to maximize the detection rate, defined as the average number of detections per unit of time, under a constraint on the false alarm rate, defined as the average number of false alarms per unit of time. Some examples modeling situations commonly encountered in the radar applications are presented to illustrate the effects of this design philosophy. [ABSTRACT FROM PUBLISHER]

In real-time monitoring systems, fine-grained measurements would pose great privacy threats to the participants as real-time measurements could disclose accurate people-centric activities. Differential privacy has been proposed to formalize and guide the design of privacy-preserving schemes. Nonetheless, due to the correlations and high fluctuations in time-series data, it is hard to achieve an effective privacy and utility tradeoff by differential privacy mechanisms. To address this issue, in this paper, we first proposed novel multi-dimensional decomposition based schemes to compress the noise and enhance the utility in differential privacy. The key idea is to decompose the measurements into multi-dimensional records and to achieve differential privacy in bounded dimensions so that the error caused by unbounded measurements can be significantly reduced. We then extended our developed scheme and developed a binary decomposition scheme for privacy-preserving time-series aggregation in real-time monitoring systems. Through a combination of extensive theoretical analysis and experiments, our data shows that our proposed schemes can effectively improve usability while achieving the same level of differential privacy than existing schemes. [ABSTRACT FROM AUTHOR]

Scheduling and dispatching tools for high-performance computing (HPC) machines have the key role of mapping jobs to the available resources, trying to maximize performance and quality-of-service (QoS). Allocation and Scheduling in the general case are well-known NP-hard problems, forcing commercial schedulers to adopt greedy approaches to improve performance and QoS. Search-based approaches featuring the exploration of the solution space have seldom been employed in this setting, but mostly applied in off-line scenarios. In this paper, we present the first search-based approach to job allocation and scheduling for HPC machines, working in a production environment. The scheduler is based on Constraint Programming, an effective programming technique for optimization problems. The resulting scheduler is flexible, as it can be easily customized for dealing with heterogeneous resources, user-defined constraints and different metrics. We evaluate our solution both on virtual machines using synthetic workloads, and on the Eurora HPC with production workloads. Tests on a wide range of operating conditions show significant improvements in waitings and QoS in mid-tier HPC machines w.r.t state-of-the-art commercial rule-based dispatchers. Furthermore, we analyze the conditions under which our approach outperforms commercial approaches, to create a portfolio of scheduling algorithms that ensures robustness, flexibility and scalability. [ABSTRACT FROM AUTHOR]