ALBERT

Beschreibung: Digital circuits are expected to increasingly suffer from more hard faults due to technology scaling. Especially, a single hard fault in ALU (Arithmetic Logic Unit) might lead to a total failure in processors or significantly reduce their performance. To address these increasingly important problems, we propose a novel cost-efficient fault-tolerant mechanism for the ALU, called LIZARD. LIZARD employs two half-word ALUs, instead of a single full-word ALU, to perform computations with concurrent fault detection. When a fault is detected, the two ALUs are partitioned into four quarter-word ALUs. After diagnosing and isolating a faulty quarter-word ALU, LIZARD continues its operation using the remaining ones, which can detect and isolate another fault. Even though LIZARD uses narrow ALUs for computations, it adds negligible performance overhead through exploiting predictability of the results in the arithmetic computations. We also present the architectural modifications when employing LIZARD for scalar as well as superscalar processors. Through comparative evaluation, we demonstrate that LIZARD outperforms other competitive fault-tolerant mechanisms in terms of area, energy consumption, performance and reliability.

Beschreibung: Information searches are the most common application within social networks. Normally, the social network is modeled as a network graph, consisting of nodes (In the rest of the paper, unless otherwise specified, we will use the terms “user” and “node” interchangeably.) representing users within the network and edges representing relationships between users. Choosing the appropriate nodes to form an auxiliary structure for supporting the effective query message spreading can reduce the troublesome repeated queries. To accomplish this, a hybrid search (HS) scheme is proposed. If the query message is received by a node belonging the auxiliary structure constructed by dynamic weighted distributed label clustering (DW-DLC), it would be flooded to all neighbors of the visited node; otherwise, it would be forwarded to one neighbor of the visited node. The DW-DLC based auxiliary structure can accelerate the process of obtaining required information within the network. The simulation results show that the HS+DW-DLC scheme can reduce the average searching delay time, even in a required-information-scarce social network. In addition, the proposed scheme can generate a relatively low amount of repeated messages to lower repeatedly asking social network users.

Beschreibung: This paper presents a derivation of four radix-2 division algorithms by digit recurrence. Each division algorithm selects a quotient digit from the over-redundant digit set {−2, −1, 0, 1, 2}, and the selection of each quotient digit depends only on the two most-significant digits of the partial remainder in a redundant representation. Two algorithms use a two’s complement representation for the partial remainder and carry-save additions, and the other two algorithms use a binary signed-digit representation for the partial remainder and carry-free additions. Three algorithms are novel. The fourth algorithm has been presented before. Results from the synthesized netlists show that two of our fastest algorithms achieve an improvement of 10 percent in latency per iteration over a standard radix-2 SRT algorithm at the cost of 36 percent more power and 50 percent more area.

Beschreibung: We present WaFS, a user-level file system, and a related scheduling algorithm for scientific workflow computation in the cloud. WaFS’s primary design goal is to automatically detect and gather the explicit and implicit data dependencies between workflow jobs, rather than high-performance file access. Using WaFS’s data, a workflow scheduler can either make effective cost-performance tradeoffs or improve storage utilization. Proper resource provisioning and storage utilization on pay-as-you-go clouds can be more cost effective than the uses of resources in traditional HPC systems. WaFS and the scheduler controls the number of concurrent workflow instances at runtime so that the storage is well used, while the total makespan (i.e., turnaround time for a workload) is not severely compromised. We describe the design and implementation of WaFS and the new workflow scheduling algorithm based on our previous work. We present empirical evidence of the acceptable overheads of our prototype WaFS and describe a simulation-based study, using representative workflows, to show the makespan benefits of our WaFS-enabled scheduling algorithm.

Beschreibung: This paper presents an anomaly detection model that is granular and distributed to accurately and efficiently identify sensed data anomalies within wireless sensor networks. A more decentralised mechanism is introduced with wider use of in-network processing on a hierarchical sensor node topology resulting in a robust framework for dynamic data domains. This efficiently addresses the big data issue that is encountered in large scale industrial sensor network applications. Data vectors on each node’s observation domain is first partitioned using an unsupervised approach that is adaptive regarding dynamic data streams using cumulative point-wise entropy and average relative density . Second order statistical analysis applied on average relative densities and mean entropy values is then used to differentiate anomalies through robust and adaptive thresholds that are responsive to a dynamic environment. Anomaly detection is then performed in a non-parametric and non-probabilistic manner over the different network tiers in the hierarchical topology in offering increased granularity for evaluation. Experiments were performed extensively using both real and artificial data distributions representative of different dynamic and multi-density observation domains. Results demonstrate higher accuracies in detection as more than 94 percent accompanied by a desirable reduction of more than 85 percent in communication costs when compared to existing centralized methods.

Beschreibung: The problem of securing data present on USB memories and SD cards has not been adequately addressed in the cryptography literature. While the formal notion of a tweakable enciphering scheme (TES) is well accepted as the proper primitive for secure data storage, the real challenge is to design a low cost TES which can perform at the data rates of the targeted memory devices. In this work, we provide the first answer to this problem. Our solution, called STES, combines a stream cipher with a XOR universal hash function. The security of STES is rigorously analyzed in the usual manner of provable security approach. By carefully defining appropriate variants of the multi-linear hash function and the pseudo-dot product based hash function we obtain controllable trade-offs between area and throughput. We combine the hash function with the recent hardware oriented stream ciphers, namely Mickey, Grain and Trivium. Our implementations are targeted towards two low cost FPGAs—Xilinx Spartan 3 and Lattice ICE40. Simulation results demonstrate that the speeds of encryption/decryption match the data rates of different USB and SD memories. We believe that our work opens up the possibility of actually putting FPGAs within controllers of such memories to perform low-level in-place encryption.

Beschreibung: Cellular automata (CAs) have been widely used to model and simulate physical systems and processes. CAs have also been successfully used as a VLSI architecture that proved to be very efficient at least in terms of silicon-area utilization and clock-speed maximization. Quantum cellular automata (QCAs) as one of the promising emerging technologies for nanoscale and quantum computing circuit implementation, provides very high scale integration, very high switching frequency and extremely low power characteristics. In this paper we present a new automated design architecture and a tool, namely DATICAQ (Design Automation Tool of 1-D CAs using QCAs), that builds a bridge between 1-D CAs as models of physical systems and processes and 1-D QCAs as nanoelectronic architecture. The QCA implementation of CAs not only drives the already developed CAs circuits to the nanoelectronics era but improves their performance significantly. The inputs of the proposed architecture are CA dimensionality, size, local rule, and initial and boundary conditions imposed by the particular problem. DATICAQ produces as output the layout of the QCA implementation of the particular 1-D CA model. Simulations of CA models for zero and periodic boundary conditions and the corresponding QCA circuits showed that the CA models have been successfully implemented.

Beschreibung: Role-based access control is an important access control method for securing computer systems. A role-based access control policy can be implemented incorrectly due to various reasons, such as programming errors. Defects in the implementation may lead to unauthorized access and security breaches. To reveal access control defects, this paper presents a model-based approach to automated generation of executable access control tests using predicate/transition nets. Role-permission test models are built by integrating declarative access control rules with functional test models or contracts (preconditions and postconditions) of the associated activities (the system functions). The access control tests are generated automatically from the test models to exercise the interactions of access control activities. They are transformed into executable code through a model-implementation mapping that maps the modeling elements to implementation constructs. The approach has been implemented in an industry-adopted test automation framework that supports the generation of test code in a variety of languages. The full model-based testing process has been applied to three systems implemented in Java. The effectiveness is evaluated through mutation analysis of role-based access control rules. The experiments show that the model-based approach is highly effective in detecting the seeded access control defects.

Beschreibung: Heterogeneous multiprocessor systems, which are composed of a mix of processing elements, such as commodity multicore processors, graphics processing units (GPUs), and others, have been widely used in scientific computing community. Software applications incorporate the code designed and optimized for different types of processing elements in order to exploit the computing power of such heterogeneous computing systems. In this paper, we consider the problem of optimal distribution of the workload of data-parallel scientific applications between processing elements of such heterogeneous computing systems. We present a solution that uses functional performance models (FPMs) of processing elements and FPM-based data partitioning algorithms. Efficiency of this approach is demonstrated by experiments with parallel matrix multiplication and numerical simulation of lid-driven cavity flow on hybrid servers and clusters.

Beschreibung: In this paper, we propose a new notion called $k$ -times attribute-based anonymous access control , which is particularly designed for supporting cloud computing environment. In this new notion, a user can authenticate himself/herself to the cloud computing server anonymously. The server only knows the user acquires some required attributes, yet it does not know the identity of this user. In addition, we provide a $k$ -times limit for anonymous access control. That is, the server may limit a particular set of users (i.e., those users with the same set of attribute) to access the system for a maximum $k$ -times within a period or an event. Further additional access will be denied. We also prove the security of our instantiation. Our implementation result shows that our scheme is practical.

Beschreibung: In face of high partial and complete disk failure rates and untimely system crashes, the executions of low-priority background tasks become increasingly frequent in large-scale data centers. However, the existing algorithms are all reactive optimizations and only exploit the temporal locality of workloads to reduce the user I/O requests during the low-priority background tasks. To address the problem, this paper proposes Intelligent Data Outsourcing (IDO), a zone-based and proactive data migration optimization, to significantly improve the efficiency of the low-priority background tasks. The main idea of IDO is to proactively identify the hot data zones of RAID-structured storage systems in the normal operational state. By leveraging the prediction tools to identify the upcoming events, IDO proactively migrates the data blocks belonging to the hot data zones on the degraded device to a surrogate RAID set in the large-scale data centers. Upon a disk failure or crash reboot, most user I/O requests addressed to the degraded RAID set can be serviced directly by the surrogate RAID set rather than the much slower degraded RAID set. Consequently, the performance of the background tasks and user I/O performance during the background tasks are improved simultaneously. Our lightweight prototype implementation of IDO and extensive trace-driven experiments on two case studies demonstrate that, compared with the existing state-of-the-art approaches, IDO effectively improves the performance of the low-priority background tasks. Moreover, IDO is portable and can be easily incorporated into any existing algorithms for RAID-structured storage systems.

Beschreibung: Cloud computing that provides elastic computing and storage resource on demand has become increasingly important due to the emergence of “big data”. Cloud computing resources are a natural fit for processing big data streams as they allow big data application to run at a scale which is required for handling its complexities (data volume, variety and velocity). With the data no longer under users’ direct control, data security in cloud computing is becoming one of the most concerns in the adoption of cloud computing resources. In order to improve data reliability and availability, storing multiple replicas along with original datasets is a common strategy for cloud service providers. Public data auditing schemes allow users to verify their outsourced data storage without having to retrieve the whole dataset. However, existing data auditing techniques suffers from efficiency and security problems. First, for dynamic datasets with multiple replicas, the communication overhead for update verifications is very large, because each update requires updating of all replicas, where verification for each update requires O(log n ) communication complexity. Second, existing schemes cannot provide public auditing and authentication of block indices at the same time. Without authentication of block indices, the server can build a valid proof based on data blocks other than the blocks client requested to verify. In order to address these problems, in this paper, we present a novel public auditing scheme named MuR-DPA. The new scheme incorporated a novel authenticated data structure (ADS) based on the Merkle hash tree (MHT), which we call MR-MHT. To support full dynamic data updates and authentication of block indices, we included rank and level values in computation of MHT nodes. In contrast to existing schemes, level values of nodes in MR-MHT are assigned in a top-down order, and all replica blocks for each data block are organized into a - ame replica sub-tree. Such a configuration allows efficient verification of updates for multiple replicas. Compared to existing integrity verification and public auditing schemes, theoretical analysis and experimental results show that the proposed MuR-DPA scheme can not only incur much less communication overhead for both update verification and integrity verification of cloud datasets with multiple replicas, but also provide enhanced security against dishonest cloud service providers.

Beschreibung: This article presents results from the integration of a noncontact physiological radar monitoring system (PRMS) with a type I polysomnography (PSG) system to perform sleep monitoring. The PRMS system consists of two continuous-wave Doppler radars operating at the industrial, scientific, and medical (ISM) band of 2.45 GHz. The system can acquire data, perform digital processing, and output appropriate conventional analog outputs with a latency of approximately 130 ms, which can be recorded and displayed by a gold standard sleep monitoring system along with other standard sensor measurements. Radar data was also used to successfully detect paradoxical motion that was simulated using linear movers and to categorize normal breathing, apnea, and hypopnea in sleeping subjects with obstructive sleep apnea (OSA).

Beschreibung: A quantitative and explicit validation of the performance and safety of microwave systems and devices that have electromagnetic interaction with the human body is critical in the technological development process. Although a numerical model of the system environment can be ideally simulated, it cannot reflect the realistic environment that is vulnerable to various electrical, mechanical, and environmental interferences. Hence, the presence of the human body is the best measurement environment for these systems. However, newly designed devices/ systems that rely on the human body electromagnetic field interactions require multiple tests/measurements under a controlled environment. This environment is needed to validate the performance in all the possible scenarios of operation and make sure of the safety of those devices and systems. For example, a breast imaging system needs to be evaluated by detecting tumors in multiple locations, and it is unthinkable to do that on a real patient; hence, breast phantoms are needed to obtain an optimum system design and algorithms before moving to human clinical trials. Moreover, some experiments, such as the specific absorption rate (SAR) and hyperthermia, cannot be done on human beings due to the need to monitor the variation of the power intensity and temperature inside tissues. Employing live human participants for testing devices exposes the entire test procedure to several inherent uncertainties, such as respiratory movement, cardiovascular vibration, and variable skin humidity in addition, of course, to the safety concern of the new devices. Also, the application of the devices and systems on human subjects or human-related materials is a serious ethical issue where the researchers must receive an ethical clearance from the proper authorities, and it can be difficult to reasonably estimate and investigate the level of risks from various scientific, physical, and psychological aspects beforehand. Thus, the utilization of ar- ificial tissue-emulating (ATE) phantoms is highly beneficial for testing a device or system.

Beschreibung: Bandwidth reservation has been recognized as a value-added service to the cloud provider in recent years. We consider an open market of cloud bandwidth reservation, in which cloud providers offer bandwidth reservation services to cloud tenants, especially online streaming service providers, who have strict requirements on the amount of bandwidth to guarantee their quality of services. In this paper, we model the open market as a double-sided auction, and propose the first family of ST rategy-proof double A uctions for multi-cloud, multi-tenant bandwidth R eservation (STAR). STAR contains two auction mechanisms. The first one, STAR-Grouping, divides the tenants into groups by a bid-independent way, and carefully matches the cloud providers with the tenant groups to form good trades. The second one, STAR-Padding, greedily matches the cloud providers with the tenants, and fills the partially reserved cloud provider(s) with a novel virtual padding tenant who can be a component of the auctioneer. Our analysis shows that both of the two auction mechanisms achieve strategy-proofness and ex-post budget balance. Our evaluation results show that they achieve good performance in terms of social welfare, cloud bandwidth utilization, and tenant satisfaction ratio.

Beschreibung: In a distributed real-time system (DRTS), jobs are often executed on a number of processors and must complete by their end-to-end deadlines. Job deadline requirements may be violated if resource competition among different jobs on a given processor is not considered. This paper introduces a distributed, locally optimal algorithm to assign local deadlines to the jobs on each processor without any restrictions on the mappings of the applications to the processors in the distributed soft real-time system. Improvedschedulability results are achieved by the algorithm since disparate workloads among the processors due to competing jobs havingdifferent paths are considered. Given its distributed nature, the proposed algorithm is adaptive to dynamic changes of the applications and avoids the overhead of global clock synchronization. In order to make the proposed algorithm more practical, two derivatives of the algorithm are proposed and compared. Simulation results based on randomly generated workloads indicate that the proposed approach outperforms existing work both in terms of the number of feasible jobs (between 51% and 313% on average) and the number of feasible task sets (between 12% and 71% on average).

Beschreibung: Reproducibility, i.e. getting bitwise identical floating point results from multiple runs of the same program, is a property that many users depend on either for debugging or correctness checking in many codes [10] . However, the combination of dynamic scheduling of parallel computing resources, and floating point nonassociativity, makes attaining reproducibility a challenge even for simple reduction operations like computing the sum of a vector of numbers in parallel. We propose a technique for floating point summation that is reproducible independent of the order of summation. Our technique uses Rump’s algorithm for error-free vector transformation [7] , and is much more efficient than using (possibly very) high precision arithmetic. Our algorithm reproducibly computes highly accurate results with an absolute error bound of $n cdot 2^{-28} cdot macheps cdot max _i |v_i|$ at a cost of $7n$ FLOPs and a small constant amount of extra memory usage. Higher accuracies are also possible by increasing the number of error-free transformations. As long as all operations are performed in to-nearest rounding mode, results computed by the proposed algorithms are reproducible for any run on any platform. In particular, our algorithm requires the minimum number of reductions, i.e. one reduction of an array of six double precision floating point numbers per sum, and hence is well suited for massively parallel environments.

Beschreibung: In recent years, embedded dynamic random-access memory (eDRAM) technology has been implemented in last-level caches due to its low leakage energy consumption and high density. However, the fact that eDRAM presents slower access time than static RAM (SRAM) technology has prevented its inclusion in higher levels of the cache hierarchy. This paper proposes to mingle SRAM and eDRAM banks within the data array of second-level (L2) caches. The main goal is to achieve the best trade-off among performance, energy, and area. To this end, two main directions have been followed. First, this paper explores the optimal percentage of banks for each technology. Second, the cache controller is redesigned to deal with performance and energy. Performance is addressed by keeping the most likely accessed blocks in fast SRAM banks. In addition, energy savings are further enhanced by avoiding unnecessary destructive reads of eDRAM blocks. Experimental results show that, compared to a conventional SRAM L2 cache, a hybrid approach requiring similar or even lower area speedups the performance on average by 5.9 percent, while the total energy savings are by 32 percent. For a 45 nm technology node, the energy-delay-area product confirms that a hybrid cache is a better design than the conventional SRAM cache regardless of the number of eDRAM banks, and also better than a conventional eDRAM cache when the number of SRAM banks is an eighth of the total number of cache banks.

Beschreibung: Nearly all of the currently used signature schemes, such as RSA or DSA, are based either on the factoring assumption or the presumed intractability of the discrete logarithm problem. As a consequence, the appearance of quantum computers or algorithmic advances on these problems may lead to the unpleasant situation that a large number of today’s schemes will most likely need to be replaced with more secure alternatives. In this work we present such an alternative—an efficient signature scheme whose security is derived from the hardness of lattice problems. It is based on recent theoretical advances in lattice-based cryptography and is highly optimized for practicability and use in embedded systems. The public and secret keys are roughly $1.5$  kB and $0.3$  kB long, while the signature size is approximately $1.1$  kB for a security level of around $80$ bits. We provide implementation results on reconfigurable hardware (Spartan/Virtex-6) and demonstrate that the scheme is scalable, has low area consumption, and even outperforms classical schemes.

Beschreibung: With the rising demands on cloud services, the electricity consumption has been increasing drastically as the main operational expenditure (OPEX) to data center providers. The geographical heterogeneity of electricity prices motivates us to study the task placement problem over geo-distributed data centers. We exploit the dynamic frequency scaling technique and formulate an optimization problem that minimizes OPEX while guaranteeing the quality-of-service, i.e., the expected response time of tasks. Furthermore, an optimal solution is discovered for this formulated problem. The experimental results show that our proposal achieves much higher cost-efficiency than the traditional resizing scheme, i.e., by activating/deactivating certain servers in data centers.

Beschreibung: A new methodology for DRAM performance analysis has been proposed based on accurate characterization of DRAM bus cycles. The proposed methodology allows cycle-accurate performance analysis of arbitrary DRAM traces, obviates the need for functional simulations, allows accurate estimation of DRAM performance maximum, and enables root causing of suboptimal DRAM operation.

Beschreibung: Presents the 2015 author/subject index for this publication.

Beschreibung: Most advanced wireless communication systems use spectrally efficient complex modulation to pack more users into the crowded frequency spectrum. Complex modulation simultaneous modulates a signal's amplitude and phase (polar coordinates) or, equivalently, the I and Q components (rectangular coordinates).

Beschreibung: During at-speed test of high performance sequential ICs using scan-based Logic BIST, the IC activity factor (AF) induced by the applied test vectors is significantly higher than that experienced during its in field operation. Consequently, power droop (PD) may take place during both shift and capture phases, which will slow down the circuit under test (CUT) signal transitions. At capture, this phenomenon is likely to be erroneously recognized as due to delay faults. As a result, a false test fail may be generated, with consequent increase in yield loss. In this paper, we propose two approaches to reduce the PD generated at capture during at-speed test of sequential circuits with scan-based Logic BIST using the Launch-On-Shift scheme. Both approaches increase the correlation between adjacent bits of the scan chains with respect to conventional scan-based LBIST. This way, the AF of the scan chains at capture is reduced. Consequently, the AF of the CUT at capture, thus the PD at capture, is also reduced compared to conventional scan-based LBIST. The former approach, hereinafter referred to as Low-Cost Approach (LCA), enables a 50 percent reduction in the worst case magnitude of PD during conventional logic BIST. It requires a small cost in terms of area overhead (of approximately 1.5 percent on average), and it does not increase the number of test vectors over the conventional scan-based LBIST to achieve the same Fault Coverage (FC). Moreover, compared to three recent alternative solutions, LCA features a comparable AF in the scan chains at capture, while requiring lower test time and area overhead. The second approach, hereinafter referred to as High-Reduction Approach (HRA), enables scalable PD reductions at capture of up to 87 percent, with limited additional costs in terms of area overhead and number of required test vectors for a given target FC, over our LCA approach. Particularly, compared to two of the three recent alternative solutions mentioned above, HRA en- bles a significantly lower AF in the scan chains during the application of test vectors, while requiring either a comparable area overhead or a significantly lower test time. Compared to the remaining alternative solutions mentioned above, HRA enables a similar AF in the scan chains at capture (approximately 90 percent lower than conventional scan-based LBIST), while requiring a significantly lower test time (approximately 4.87 times on average lower number of test vectors) and comparable area overhead (of approximately 1.9 percent on average).

Beschreibung: Satellite-based systems are used countless times a day. The navigation systems in our cars and smartphones employ a minimum of seven to ten satellites to give us directions; several satellites are required when we check weather conditions and in mapping our location when we search for a local restaurant; when calling abroad, when surfing the Internet on an airplane or ocean cruise, when the Super Bowl is broadcast live worldwide-in cases like these and many more, several satellites must be used at the same time. The failure of a transmitter onboard any one of these satellites can lead to a service interruption that is eventually translated into a negative economic impact for the satellite operators. In short, reliability in space is essential.

Beschreibung: Researchers have described the concept of noise matching since at least the 1950s [1]-[4], with studies demonstrating the interrelationships among the noise factor of a low-noise amplifier (LNA), the LNA's noise parameters, and the signal-source impedance Z〈sub>s〈/sub>. Noise matching is accomplished when an LNA is driven by a signal source, the impedance (or admittance) of which is designed-perhaps using a matching network-to equal the LNA's optimum signal-source impedance for minimum noise, or Zopt. The complex Z〈sub>opt〈/sub> = G〈sub>opt〈/sub> + jX〈sub>opt〈/sub> represents two of the four noise parameters that completely characterize the noise behavior of a linear two-port device, such as an LNA. The other two noise parameters are the minimum noise factor, F〈sub>min〈/sub> , and the Lange invariant N [5], [6], which is, arguably, a more fundamental parameter than the often-used equivalent noise resistance, R〈sub>n〈/sub>.

Beschreibung: The brain may be seen as an electronic network made up of neurons and their connections. The structure of a neuron consists of both higher - conducting "passive" membranes and an "active" component of transmembrane voltage; the two are mediated by intra- and extra-cellular ion concentrations in a water milieu.

Beschreibung: Extensive research in the electromagnetics area has been conducted recently with the goal of developing novel artificial metamaterials-or left-handed (LH) materials-at microwave frequencies. The idea of negative magnetic permeability and negative electric permittivity as electromagnetic properties for LH materials was initially theorized by Veselago in 1968 [1]. LH materials are not found in nature, so engineers must modify a structure's geometry to achieve LH behavior.

Beschreibung: Oscillators are integral to the design of modern communications systems. Generally, these oscillators act as part of a synthesizer and are voltage controlled, meaning that the frequency is determined by tuning diodes, frequently called varactors. The applied dc voltage varies the frequency. For high-performance circuits, the Colpitts oscillator is most frequently selected [1]-[30].

Beschreibung: Efficiency enhancement techniques for high-power amplification systems are now mature technologies, with Doherty power amplifiers (PAs) being widely used in field-deployed wireless base stations. A typical Doherty PA consists of two parallel amplifiers (a carrier amplifier, biased in class-AB, and a peaking amplifier, biased in class-C), an input analog splitter, and a nonisolated output power combiner. The operation of the Doherty PA is based on an active load modulation mechanism, which allows the carrier and peaking amplifiers to operate into optimal load-impedance trajectories that vary according to the amplitude of the input signal. This, in principle, results in increasing the average efficiency of the Doherty PA without compromising its linearity.

Beschreibung: Welcome to a further installment of "New Products" in IEEE Microwave Magazine. In this issue, we present seven new items that may be of interest to the RF/microwave and wireless communities.