169,825 research outputs found
Thermal-Safe Test Scheduling for Core-Based System-on-a-Chip Integrated Circuits
No full textOverheating has been acknowledged as a major problem during the testing of complex system-on-chip (SOC) integrated circuits. Several power-constrained test scheduling solutions have been recently proposed to tackle this problem during system integration. However, we show that these approaches cannot guarantee hot-spot-free test schedules because they do not take into account the non-uniform distribution of heat dissipation across the die and the physical adjacency of simultaneously active cores. This paper proposes a new test scheduling approach that is able to produce short test schedules and guarantee thermal-safety at the same time. Two thermal-safe test scheduling algorithms are proposed. The first algorithm computes an exact (shortest) test schedule that is guaranteed to satisfy a given maximum temperature constraint. The second algorithm is a heuristic intended for complex systems with a large number of embedded cores, for which the exact thermal-safe test scheduling algorithm may not be feasible. Based on a low-complexity test session thermal cost model, this algorithm produces near-optimal length test schedules with significantly less computational effort compared to the optimal algorithm
Scan architecture with mutually exclusive scan segment activation for shift and capture power reduction
No full textPower dissipation during scan testing is becoming an important concern as design sizes and gate densities increase. While several approaches have been recently proposed for reducing power dissipation during the shift cycle (minimum transition don't care fill, special scan cells and scan chain partitioning), very little work has been carried out towards reducing the peak power during test response capture and the few existing approaches for reducing capture power rely on complex ATPG algorithms. This paper proposes a scan architecture with mutually exclusive scan segment activation which overcomes the shortcomings of previous approaches. The proposed architecture achieves both shift and capture power reduction with no impact on the performance of the design, and with minimal impact on area and testing time (typically 2-3%). An algorithmic procedure for assigning flip-flips to scan segments enables reuse of test patterns generated by standard ATPG tools. An implementation of the proposed method had been integrated into an automated design flow using commercial synthesis and simulation tools which was used on a wide range of benchmark designs. Reductions up to 57% in average power, and up to 44% and 34% in peak power dissipation during shift and capture cycles, respectively, were obtained when using two scan segments. Increasing the number of scan segments to six leads to reductions of 96% and 80% in average power and respectively maximum number of simultaneous transitions
Rapid generation of thermal-safe test schedules
No full textOverheating has been acknowledged as a major issue in testing complex SOCs. Several power constrained system-level DFT solutions (power constrained test scheduling) have been recently proposed to tackle this problem. However, as it will be shown in this paper, imposing a chip-level maximum power constraint doesn't necessarily avoid local overheating due to the non-uniform distribution of power across the chip. This paper proposes a new approach for dealing with overheating during test, by embedding thermal awareness into test scheduling. The proposed approach facilitates rapid generation of thermal-safer test schedules without requiring time-consuming thermal simulations. This is achieved by employing a low-complexity test session thermal model used to guide the test schedule generation algorithm. This approach reduces the chances of a design re-spin due to potential overheating during test
Group invariance of global generalized solutions of nonlinear PDEs in Colombeau algebras and in the Dedekind order completion method
No full textThesis (PhD )--University of Pretoria, 1993.In this thesis a theoretical framework is provided within which large classes of nonlinear Lie groups of transformations are defined on spaces of generalized functions which yield global generalized solutions for large classes of nonlinear partial differential equations (PDEs). Although these function spaces contain the L Schwartz distributions, this theory stays within finite dimensional manifolds. It is shown how Lie symmetry groups for classical solutions of nonlinear PDEs can be extended to symmetry groups for global generalized solutions. For the first time in the literature, applications are given of the nonlinear group invariance of global weak solutions of nonlinear PDEs, under transformations defined on the whole domains of definition of those solutions. The major difficulty with the study of Lie group invariance of -mlutions of nonlinear PDEs has been the absence of a theory for the existence of solutions for general nonlinear PDEs. Also, many of the known classical solutions of specific nonlinear PDEs are not C -smooth on the whole domain of definition of these PDEs, typically exhibiting singularities. In the last few decades, functional analytic methods have produced existence results concerning global generalized solutions for several particular classes of nonlinear PDEs. However, these generalized solutions are usually linear functionals, such as the L Schwartz distributions, making the study of nonlinear group invariance particularly difficult, even though such transformations arise naturally with nonlinear PDEs. Furthermore, these linear functionals are defined on infinite dimensional vector spaces, making the computation of their Lie symmetry groups highly nontrivial. All of the above-mentioned difficulties are bypassed by two recent nonlinear theories of generalized functions. The first, based on algebraic solution methods, was developed by E E Rosinger, and in a particular and central case, in the independent work of J F Colombeau. The second is the more powerful, as yet unpublished, Dedekind order completion method of M O berguggenberger and E E Rosinger. Particularly the algebraic method of Rosinger and the order completion method of Oberguggenberger and Rosinger, have made available global existence results for solutions of large classes of nonlinear PDEs. In addition, the group transformations of the relevant generalized function spaces can be defined in such a way as to stay within finite dimensional manifolds which are, in fact, the original spaces of independent and dependent variables of the PDEs. It is shown here how to extend the concept of projectable group actions from classical function spaces to generalized function spaces, specifically to Colombeau's algebra of generalized functions, and to the order completion context of Oberguggenberger and Rosinger. In the case of Colombeau algebras, the same is done for more general groups. The concepts of invariant solutions and symmetry groups are also extended to include global generalized solutions. Finally, in the case of the order completion method, examples are given of the nonlinear group invariance of delta wave solutions of semilinear hyperbolic equations with rough initial data, and of Riemann solvers of the nonlinear shock wave equation.Mathematics and Applied MathematicsPh
Thermal-aware SoC test scheduling with test set partitioning and interleaving
No full textHigh temperature has become a major problem for system-on-chip testing. In order to reduce the test application time while keeping the temperatures of the cores under test within safe ranges, a thermal-aware test scheduling technique is required. This paper presents an approach to minimize the test application time and, at the same time, prevent the temperatures of cores under test going beyond given limits. We employ test set partitioning to divide test sets into shorter test sequences, and add cooling periods between test sequences so that overheating can be avoided. Moreover, test sequences from different test sets are interleaved, such that the cooling periods and the bandwidth of the test bus can be utilized for test data transportation, and hence the test application time can be reduced. The test scheduling problem is formulated as a combinatorial optimization problem, and we use the constraint logic programming (CLP) to build the optimization model and find the optimal solution. As the optimization time of the CLP-based approach increases exponentially with the problem size, we also propose a heuristic which generates longer test schedules but requires substantially shorter optimization time. Experimental results have shown the efficiency of the proposed approach
The Nash Equilibrium requires strong cooperation
No full textContrary to the customary view that the celebrated Nash-equilibrium theorem in Game Theory is paradigmatic for non-cooperative games, it is shown that, in fact, it is essentially based on a particularly strong cooperation assumption. Furthermore, in practice, this cooperation assumption is simply unrealistic.non-cooperation, strong cooperation, mixup in the Nash equilibrium
Minimizing Test Power in SRAM through Reduction of Pre-charge Activity
No full textIn this paper we analyze the test power of SRAM memories and demonstrate that the full functional pre-charge activity is not necessary during test mode because of the predictable addressing sequence. We exploit this observation in order to minimize power dissipation during test by eliminating the unnecessary power consumption associated with the pre-charge activity. This is achieved through a modified pre-charge control circuitry, exploiting the first degree of freedom of March tests, which allows choosing a specific addressing sequence. The efficiency of the proposed solution is validated through extensive Spice simulations
SystemC-based Minimum Intrusive Fault Injection Technique with Improved Fault Representation
No full textIn this paper, we propose a new SystemC-based fault injection technique that has improved fault representation in visible and on-the-fly data and signal registers. The technique is minimum intrusive since it only requires replacing the original data or signal types to fault injection enabler types. We compare the proposed simulation technique with recently reported SystemC-based techniques and show that our technique has fast simulation speed, better fault representation, while maintaining simplicity and minimum intrusion. We demonstrate fault injection capabilities in a behavioural SystemC description of MPEG-2 decoder using proposed technique and show that up to 98.9% fault representation within data and signal registers can be achieved
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Potential for agricultural recycling of struvite and zeolites to improve soil microbial physiology and mitigate CO2 emissions
No full textRecycling nutrients in agroecosystems is becoming increasingly important to promote agricultural sustainability. Struvite and nitrogen (N)-enriched zeolites produced via wastewater treatment offer the potential for nutrient recycling. However, their effects on soil properties, particularly on microbial physiology, remain largely unknown; especially regarding microbial feedback, from which losses or sequestration of essential elements may result. This study investigates the short-term (three days) physiological responses of soil microorganisms, changes in available nutrients, and the immediate effects on soil organic matter (SOM) and carbon dioxide (CO2) emissions following the application of struvite and N-enriched zeolites derived from liquid digestate, alongside natural zeolites amendments in an acidic sandy soil. All treatments increased soil pH, which emerged as a driving factor in the dissolution of labile organic carbon (C) and the microbial production of N-, C-, and phosphorus (P)-acquiring extracellular enzymes. As soil pH increased, the stoichiometric ratio of microbial biomass C (Cmic) to microbial biomass N (Nmic), along with the enzymatic C:N ratio decreased, suggesting a superior effect on microbial N-cycling compared to C-cycling. Carbon dioxide emissions increased, particularly with the application of organic fertilizer (digestate), where the highest microbial metabolic quotient reflected increased catabolic activity due to the immediate availability of organic C. Overall, zeolitized tuffs demonstrated the potential to mitigate CO2 emissions, likely due to CO2 adsorption capacity
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