A Brain-Computer Interface (BCI) aims at providing a way for controlling external devices through the utilization of brain signals. One of the challenges in electroencephalography (EEG)-based BCI is to adjust the brai...
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While applications deployed at the edge often rely on performance stability (or, at a minimum, on a predictable level of performance), variability at the edge remains a real problem [4]. This study uncovers a surprisi...
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ISBN:
(纸本)9781450382915
While applications deployed at the edge often rely on performance stability (or, at a minimum, on a predictable level of performance), variability at the edge remains a real problem [4]. This study uncovers a surprising source of variability: intrinsic variability (in performance and power consumption) among edge platforms that are nominally identical. We focus on a popular platform designed for edge applications, the NVIDIA Jetson AGX, and aim to answer the following high-level questions through rigorous statistical analysis: (i) are the edge devices in our study statistically different from each other in terms of applications' runtime performance and power draw (although they are sold under the same product model and family)?, (ii) if the differences between these edge devices are statistically significant, what is the magnitude of these differences?, and (iii) do these differences matter from the application's perspective?
Self-management research in HCI has addressed a variety of conditions. Yet, this literature has largely focused on neurotypical populations and chronic conditions that can be managed, leaving open questions of what se...
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ISBN:
(纸本)9781450380966
Self-management research in HCI has addressed a variety of conditions. Yet, this literature has largely focused on neurotypical populations and chronic conditions that can be managed, leaving open questions of what self-management might look like for populations with progressive cognitive impairment. Grounded in interviews with seventeen technology savvy people with mild to moderate dementia, our analysis reveals their use of technological and social resources as part of the work of self-management. We detail how participants design self-management systems to enable desired futures, function well in their social world, and maintain control. Our discussion broadens the notion of self-management to include future-oriented, sociotechnical, self-determinate design. We advocate for expanding the way technologists, designers, and HCI scholars view people with mild to moderate dementia to recognize them as inventive creators and capable actors in self-management.
Time series data are used in a wide variety of applications. The explosive growth of the amount of time series data poses a significant challenge in efficient data storage and query processing. Unfortunately, existing...
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Time series data are used in a wide variety of applications. The explosive growth of the amount of time series data poses a significant challenge in efficient data storage and query processing. Unfortunately, existing compression techniques either show only low to medium compression ratio on time series data, or incur significant decompression overhead during query *** propose a novel compression technique, MOST (Model-based compression with Outlier STorage) for time series data. As measurement values often change smoothly in a period of time, we divide a time series into segments of smooth changes, then compute a linear model for each segment. Since tiny errors are often acceptable in analysis tasks, we omit data points whose computed values are within a pre-specified error threshold from the actual values, thereby effectively reducing the data size. Outliers are rare but important for many applications, and therefore we store outliers explicitly. Moreover, for processing MOST compressed data, we propose a segment-outlier dual-mode query engine that computes segments as a whole as much as possible, and build a prototype MostDB. Experimental results on real-world data sets show that MOST achieves 9.45-15.04x compression ratios. Compared to existing time series databases, MostDB achieves up to 11.68x speedups for common queries from the IoTDB Benchmark.
The number of cores and the capacities of main memory in modern systems have been growing significantly. Specifically, memory scaling, although at a slower pace than computation scaling, provided opportunities for ver...
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The number of cores and the capacities of main memory in modern systems have been growing significantly. Specifically, memory scaling, although at a slower pace than computation scaling, provided opportunities for very large DRAMs with Terabytes (TBs) capacity. Consequently, addressing the performance and energy consumption bottlenecks of DRAMs is more important than ever. DRAM memory refresh operation is one of the main contributing factors to the memory overheads, especially for large capacity DRAMs used in modern servers and emerging large-scale data centers. This paper addresses the memory refresh problem by leveraging the fact that most cloud servers host virtualized systems that use similar kernels, libraries, etc. We propose and experimentally evaluate a novel approach that exploits this observation to address the DRAM refresh overhead in such systems. More specifically, in this work, we present DSM, a light-weight hardware extension in memory controller to detect the pages with same content in memory and refresh only one of them and redirect the requests to the others to this page. Our detailed experimental analysis shows that the proposed DSM design can reduce 99th percentile memory access latency by up to 2.01x, and it also reduces the overall memory energy consumption by up to 8.5%.
Controversial understandings of the coronavirus pandemic have turned data visualizations into a battleground. Defying public health officials, coronavirus skeptics on US social media spent much of 2020 creating data v...
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ISBN:
(纸本)9781450380966
Controversial understandings of the coronavirus pandemic have turned data visualizations into a battleground. Defying public health officials, coronavirus skeptics on US social media spent much of 2020 creating data visualizations showing that the government's pandemic response was excessive and that the crisis was over. This paper investigates how pandemic visualizations circulated on social media, and shows that people who mistrust the scientific establishment often deploy the same rhetorics of data-driven decision-making used by experts, but to advocate for radical policy changes. Using a quantitative analysis of how visualizations spread on Twitter and an ethnographic approach to analyzing conversations about COVID data on Facebook, we document an epistemological gap that leads pro- and anti-mask groups to draw drastically different inferences from similar data. Ultimately, we argue that the deployment of COVID data visualizations reflect a deeper sociopolitical rift regarding the place of science in public life.
Reading, adapting, and maintaining complex software can be a daunting task. We might need to refactor it to streamline the process and make the code cleaner and self-explanatory. Traditional refactoring tools guide de...
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ISBN:
(数字)9798400705021
ISBN:
(纸本)9798350351781
Reading, adapting, and maintaining complex software can be a daunting task. We might need to refactor it to streamline the process and make the code cleaner and self-explanatory. Traditional refactoring tools guide developers to achieve better-quality code. However, the feedback and assistance they provide can take considerable time. To tackle this issue, we explored the concept of Live Refactoring. This approach focuses on delivering real-time, visually-driven refactoring suggestions. That way, we prototyped a Live Refactoring Environment that visually identifies, recommends, and applies several refactorings in real-time. To validate its effectiveness, we conducted a set of experiments. Those showed that our approach significantly improved various code quality metrics and outperformed the results obtained from manually refactoring code.
This work presents the first-ever detailed and large-scale measurementanalysis of storage consumption behavior of applications (apps) on smart mobile devices. We start by carrying out a five-year longitudinal static ...
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Crop diseases and pest infestation are one of the main causes of economic losses in the agriculture business and reduction in food production. In this context, the application of techniques for early diagnosis of crop...
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Many program codes from different application domains process very large amounts of data, making their cache memory behavior critical for high performance. Most of the existing work targeting cache memory hierarchies ...
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Many program codes from different application domains process very large amounts of data, making their cache memory behavior critical for high performance. Most of the existing work targeting cache memory hierarchies focus on improving data access patterns, e.g., maximizing sequential accesses to program data structures via code and/or data layout restructuring strategies. Prior work has addressed this data locality optimization problem in the context of both single-core and multicore systems. Another dimension of optimization, which can be as equally important/beneficial as improving data access pattern is to reduce the data volume (total number of addresses) accessed by the program code. Compared to data access pattern restructuring, this volume minimization problem has relatively taken much less attention. In this work, we focus on this volume minimization problem and address it in both single-core and multi-core execution scenarios. Specifically, we explore the idea of rewriting an application program code to reduce its "memory space footprint". The main idea behind this approach is to reuse/recycle, for a given data element, a memory location that has originally been assigned to another data element, provided that the lifetimes of these two data elements do not overlap with each other. A unique aspect is that it is "distance aware", i.e., in identifying the memory/cache locations to recycle it takes into account the physical distance between the location of the core and the memory/cache location to be recycled. We present a detailed experimental evaluation of our proposed memory space recycling strategy, using five different metrics: memory space consumption, network footprint, data access distance, cache miss rate, and execution time. The experimental results show that our proposed approach brings, respectively, 33.2%, 48.6%, 46.5%, 31.8%, and 27.9% average improvements in these metrics, in the case of single-threaded applications. With the multi-threaded vers
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