Web applications can implement procedures for studying the speed of mental processes (mental chronometry) and can be administered via web browsers on most commodity desktops, laptops, smartphones, and tablets. This approach to conducting mental chronometry offers various opportunities, such as increased scale, ease of data collection, and access to specific samples. However, validity and reliability may be threatened by less accurate timing than specialized software and hardware can offer. We examined how accurately web applications time stimuli and register response times (RTs) on commodity touchscreen and keyboard devices running a range of popular web browsers. Additionally, we explored the accuracy of a range of technical innovations for timing stimuli, presenting stimuli, and estimating stimulus duration. The results offer some guidelines as to what methods may be most accurate and what mental chronometry paradigms may suitably be administered via web applications. In controlled circumstances, as can be realized in a lab setting, very accurate stimulus timing and moderately accurate RT measurements could be achieved on both touchscreen and keyboard devices, though RTs were consistently overestimated. In uncontrolled circumstances, such as researchers may encounter online, stimulus presentation may be less accurate, especially when brief durations are requested (of up to 100 ms). Differences in RT overestimation between devices might not substantially affect the reliability with which group differences can be found, but they may affect reliability for individual differences. In the latter case, measurement via absolute RTs can be more affected than measurement via relative RTs (i.e., differences in a participant's RTs between conditions).

Web applications can implement procedures for studying the speed of mental processes (mental chronometry). As web applications, these procedures can be administered via web-browsers on most commodity desktops, laptops, smartphones, and tablets. This approach to conducting mental chronometry offers various opportunities, such as increased scale, ease of data collection, and access to specific samples. However, validity and reliability may be threatened due to web applications on commodity devices having less accurate timing than specialized software and hardware. We have examined how accurately web applications time stimuli and register response times on commodity touchscreen and keyboard devices running a range of popular web-browsers. Additionally, we have explored the accuracy of a range of technical innovations for timing stimuli, presenting stimuli, and estimating stimulus duration. Results offer some guidelines as to what kind of methods may be most accurate, and what kind of mental chronometry paradigms may suitably be administered via web applications. In controlled circumstances, as can be realized in a lab setting, very accurate stimulus timing and moderately accurate Reaction Time (RT) measurements could be achieved on both touchscreen and keyboard devices. In uncontrolled circumstances, as may be encountered online, short stimulus durations (of up to 100 ms) may be inaccurate, and RT measurement may be affected by the occurrence of bi-modally distributed RT overestimations.TIMING ACCURACY OF WEB APPLICATIONS ON TOUCHSCREEN AND KEYBOARD 3

Abstract-Reduction circuits are used to reduce rows of floating point values to single values. Binary floating point operators often have deep pipelines, which may cause hazards when many consecutive rows have to be reduced.We present an algorithm by which any number of consecutive rows of arbitrary lengths can be reduced by a pipelined commutative and associative binary operator in an efficient manner. The algorithm is simple to implement, has a low latency, produces results in-order, and requires only small buffers. Besides, it uses only a single pipeline for the involved operation.The complexity of the algorithm depends on the depth of the pipeline, not on the length of the input rows.In this paper we discuss an implementation of this algorithm and we prove its correctness.

In this paper, a novel multi-target design methodology based on the concepts of transformational design, and its application to the interlaced-to-progressive scan conversion (IPSC) problem, are discussed. Starting from a single high-level behavioral specification in VHDL a direction detector used in IPSC adgorithms is mapped onto both a custom implementation and a programmable video signall processor. Results are compared with those previously obtained using different tools and methodologies. 3.4.1 IEEE 1995 CUSTOM INTEGRATED CIRCUITS C0NFE:RENCE ' SIL was developed in cooperation with Philips Research and IMEC as part of the ESPRITBPRITE project 2260.

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