6,436,424 research outputs found
Performance management at design actvity level
The overriding aim of much of the engineering design research is to improve the performance of the design process, and consequently the product development process. Much has been written within the product development literature on the performance of the product development process. This work has been largely focused on the analysis of performance at the project or program level. The ability to relate the different research and draw generic lessons from the results has been stifled by the lack of consistency on the meaning of performance both at a generic level [2] and more specifically in design/development [3]. For example, although product and process performance have been distinguished within existing work we are unclear on how these relate or may be managed effectively. This paper begins with a brief review of research in the area of performance, with particular emphasis on design/product development, highlighting the main weaknesses in work to date. A fundamental and generic model of performance, related to knowledge based activities in design, is then presented. The model describes performance in terms of its key elements, efficiency and effectiveness, and provides a basis for modelling performance across different process levels, i.e. project, program, etc
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System-level key performance indicators for building performance evaluation
Quantifying building energy performance through the development and use of key performance indicators (KPIs) is an essential step in achieving energy saving goals in both new and existing buildings. Current methods used to evaluate improvements, however, are not well represented at the system-level (e.g., lighting, plug-loads, HVAC, service water heating). Instead, they are typically only either measured at the whole building level (e.g., energy use intensity) or at the equipment level (e.g., chiller efficiency coefficient of performance (COP)) with limited insights for benchmarking and diagnosing deviations in performance of aggregated equipment that delivers a specific service to a building (e.g., space heating, lighting). The increasing installation of sensors and meters in buildings makes the evaluation of building performance at the system level more feasible through improved data collection. Leveraging this opportunity, this study introduces a set of system-level KPIs, which cover four major end-use systems in buildings: lighting, MELs (Miscellaneous Electric Loads, aka plug loads), HVAC (heating, ventilation, and air-conditioning), and SWH (service water heating), and their eleven subsystems. The system KPIs are formulated in a new context to represent various types of performance, including energy use, peak demand, load shape, occupant thermal comfort and visual comfort, ventilation, and water use. This paper also presents a database of system KPIs using the EnergyPlus simulation results of 16 USDOE prototype commercial building models across four vintages and five climate zones. These system KPIs, although originally developed for office buildings, can be applied to other building types with some adjustment or extension. Potential applications of system KPIs for system performance benchmarking and diagnostics, code compliance, and measurement and verification are discussed
Outsourcing and Firm-level Performance
Using firm-level panel data from the German cost structure survey over the period 1992 to 2000, our empirical analysis shows that firms that increased material inputs relative to internal labor costs performed better in terms of gross operating surplus than other firms. However, firms that increased external services relative to internal labor costs, thus outsourcing service functions previously provided within the firm, performed worse. In sum, our findings support the view that firms tend to overestimate the benefits accruing from outsourcing of services previously provided internally.outsourcing, firm performance, business service sector
Performance evaluation of SiC MOSFET in 5-level single phase converter
The use of silicon carbide (SiC) semiconductor power devices
has been studied and evaluated in a wide variety of
converters. The work presented in this paper shows the
performance of C2M SiC MOSFETs compared to Si devices
operating as switching elements in a 5-level, single phase,
multilevel converter. The paper describes the multilevel
converter platform used to undertake the evaluation study and
experimental results for the operating temperature of the
MOSFETs, and conversion efficiency are shown for
frequencies ranging from 20 kHz to 80 kHz. Finally, a
discussion of the results obtained to highlight the differences
in the performance of the Si and SiC devices and the
feasibility of using SiC in MLC
Performance monitoring at the task and the response level
How errors and confl ict are processed in the human brain, has been extensively investigated over the last decades. In this review, we argue that error research has mainly focused on one type of errors, namely errors at the response level. Furthermore, research on conflict and errors has primarily used a very restricted set of experimental paradigms, raising the question as to whether the results from this research can be generalized to other forms of errors and confl ict. We thus argue to approach errors and confl ict from a broader perspective
Hierarchical Beamforming: Resource Allocation, Fairness and Flow Level Performance
We consider hierarchical beamforming in wireless networks. For a given
population of flows, we propose computationally efficient algorithms for fair
rate allocation including proportional fairness and max-min fairness. We next
propose closed-form formulas for flow level performance, for both elastic (with
either proportional fairness and max-min fairness) and streaming traffic. We
further assess the performance of hierarchical beamforming using numerical
experiments. Since the proposed solutions have low complexity compared to
conventional beamforming, our work suggests that hierarchical beamforming is a
promising candidate for the implementation of beamforming in future cellular
networks.Comment: 34 page
Transformations of High-Level Synthesis Codes for High-Performance Computing
Specialized hardware architectures promise a major step in performance and
energy efficiency over the traditional load/store devices currently employed in
large scale computing systems. The adoption of high-level synthesis (HLS) from
languages such as C/C++ and OpenCL has greatly increased programmer
productivity when designing for such platforms. While this has enabled a wider
audience to target specialized hardware, the optimization principles known from
traditional software design are no longer sufficient to implement
high-performance codes. Fast and efficient codes for reconfigurable platforms
are thus still challenging to design. To alleviate this, we present a set of
optimizing transformations for HLS, targeting scalable and efficient
architectures for high-performance computing (HPC) applications. Our work
provides a toolbox for developers, where we systematically identify classes of
transformations, the characteristics of their effect on the HLS code and the
resulting hardware (e.g., increases data reuse or resource consumption), and
the objectives that each transformation can target (e.g., resolve interface
contention, or increase parallelism). We show how these can be used to
efficiently exploit pipelining, on-chip distributed fast memory, and on-chip
streaming dataflow, allowing for massively parallel architectures. To quantify
the effect of our transformations, we use them to optimize a set of
throughput-oriented FPGA kernels, demonstrating that our enhancements are
sufficient to scale up parallelism within the hardware constraints. With the
transformations covered, we hope to establish a common framework for
performance engineers, compiler developers, and hardware developers, to tap
into the performance potential offered by specialized hardware architectures
using HLS
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