The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Chau Yuen - One of the best experts on this subject based on the ideXlab platform.

  • sensor fusion for public Space Utilization monitoring in a smart city
    IEEE Internet of Things Journal, 2018
    Co-Authors: Billy Pik Lik Lau, Nipun Wijerathne, Chau Yuen
    Abstract:

    Public Space Utilization is crucial for urban developers to understand how efficient a place is being occupied in order to improve existing or future infrastructures. In a smart cities approach, implementing public Space monitoring with Internet-of-Things (IoT) sensors appear to be a viable solution. However, choice of sensors often is a challenging problem and often linked with scalability, coverage, energy consumption, accuracy, and privacy. To get the most from low cost sensor with aforementioned design in mind, we proposed data processing modules for capturing public Space Utilization with renewable wireless sensor network (RWSN) platform using pyroelectric infrared (PIR) and analog sound sensor. We first proposed a calibration process to remove false alarm of PIR sensor due to the impact of weather and environment. We then demonstrate how the sounds sensor can be processed to provide various insight of a public Space. Lastly, we fused both sensors and study a particular public Space Utilization based on one month data to unveil its usage.

  • spatial and temporal analysis of urban Space Utilization with renewable wireless sensor network
    International Conference on Big Data, 2016
    Co-Authors: Billy Pik Lik Lau, Tanmay Chaturvedi, Marakkalage Sumudu Hasala, Chau Yuen
    Abstract:

    Space Utilization are important elements for a smart city to determine how well public Space are being utilized. Such information could also provide valuable feedback to the urban developer on what are the factors that impact Space Utilization. The spatial and temporal information for Space Utilization can be studied and further analyzed to generate insights about that particular Space. In our research context, these elements are translated to part of big data and Internet of things (IoT) to eliminate the need of on site investigation. However, there are a number of challenges for large scale deployment, eg. hardware cost, computation capability, communication bandwidth, scalability, data fragmentation, and resident privacy etc. In this paper, we designed and prototype a Renewable Wireless Sensor Network (RWSN), which addressed the aforementioned challenges. Finally, analyzed results based on initial data collected is presented.

  • BDCAT - Spatial and temporal analysis of urban Space Utilization with renewable wireless sensor network
    Proceedings of the 3rd IEEE ACM International Conference on Big Data Computing Applications and Technologies, 2016
    Co-Authors: Billy Pik Lik Lau, Tanmay Chaturvedi, Marakkalage Sumudu Hasala, Chau Yuen
    Abstract:

    Space Utilization are important elements for a smart city to determine how well public Space are being utilized. Such information could also provide valuable feedback to the urban developer on what are the factors that impact Space Utilization. The spatial and temporal information for Space Utilization can be studied and further analyzed to generate insights about that particular Space. In our research context, these elements are translated to part of big data and Internet of things (IoT) to eliminate the need of on site investigation. However, there are a number of challenges for large scale deployment, eg. hardware cost, computation capability, communication bandwidth, scalability, data fragmentation, and resident privacy etc. In this paper, we designed and prototype a Renewable Wireless Sensor Network (RWSN), which addressed the aforementioned challenges. Finally, analyzed results based on initial data collected is presented.

Wei-kuan Shih - One of the best experts on this subject based on the ideXlab platform.

  • Co-Optimizing Storage Space Utilization and Performance for Key-Value Solid State Drives
    IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2019
    Co-Authors: Yen-ting Chen, Ming-chang Yang, Yuan-hao Chang, Tseng-yi Chen, Hsin-wen Wei, Wei-kuan Shih
    Abstract:

    Growing demand for key-value store applications is building a strong momentum for the commercialization of key-value hard disk drives. To achieve better performance, flash-based solid state drive is the next ideal candidate for commercialization in the foreseeable future. However, the existing fixed-sized management strategies of flash-based devices would potentially result in low storage Space Utilization when managing variable-sized key-value data. In addition, the low storage Space Utilization would further lead to the degradation of device performance, due to low invalid data Space reclamation efficiency. The Space Utilization issue motivates this paper to propose a key-value flash translation layer design to improve storage Space Utilization as well as the performance of the key-value solid state drives. A series of experiments was conducted to evaluate the proposed design, and the experiment results of Space Utilization and device performance are very encouraging.

  • On Space Utilization Enhancement of File Systems for Embedded Storage Systems
    ACM Transactions on Embedded Computing Systems, 2017
    Co-Authors: Tseng-yi Chen, Yuan-hao Chang, Hsin-wen Wei, Shuo-han Chen, Nien-i Hsu, Wei-kuan Shih
    Abstract:

    Since the mid-2000s, mobile/embedded computing systems conventionally have limited computing power, Random Access Memory (RAM) Space, and storage capacity due to the consideration of their cost, energy consumption, and physical size. Recently, some of these systems, such as mobile phone and embedded consumer electronics, have more powerful computing capability, so they manage their data in small flash storage devices (e.g., Embedded Multi Media Card (eMMC) and Secure Digital (SD) cards) with a simple file system. However, the existing file systems usually have low Space Utilization for managing small files and the tail data of large files. In this work, we thus propose a dynamic tail packing scheme to enhance the Space Utilization of file systems over flash storage devices in embedded computing systems by dynamically aggregating/packing the tail data of (small) files together. To evaluate the benefits and overheads of the proposed scheme, we theoretically formulate analysis equations for obtaining the best settings in the dynamic tail packing scheme. Additionally, the proposed scheme was implemented in the file system of Linux operating systems to evaluate its capability. The results demonstrate that the proposed scheme could significantly improve the Space Utilization of existing file systems.

  • ASP-DAC - KVFTL: Optimization of storage Space Utilization for key-value-specific flash storage devices
    2017 22nd Asia and South Pacific Design Automation Conference (ASP-DAC), 2017
    Co-Authors: Yen-ting Chen, Ming-chang Yang, Yuan-hao Chang, Tseng-yi Chen, Hsin-wen Wei, Wei-kuan Shih
    Abstract:

    The strong momentum of key-value store applications drives the commercialization of key-value-specific hard disk drives. To achieve higher degree of performance, the specific flash-based solid state drives would be also commercialized for key-value store applications in the foreseeable future. However, the existing fixed-sized management strategies of flash-based devices would potentially result in low storage Space Utilization on managing variable-sized key-value data. This problem inspires this paper to propose a key-value flash translation layer (KVFTL) design to improve the storage Space Utilization of the key-value-specific solid state drives (KVSSDs). A series of experiments was conducted to evaluated the proposed design, and the experimental results on Space Utilization and device performance are very encouraging.

  • Multi-Grained Block Management to Enhance the Space Utilization of File Systems on PCM Storages
    IEEE Transactions on Computers, 2016
    Co-Authors: Tseng-yi Chen, Ming-chang Yang, Yuan-hao Chang, Hsin-wen Wei, Yun-jhu Chen, Wei-kuan Shih
    Abstract:

    Phase-change memory (PCM) is a promising candidate as a storage medium to resolve the performance gap between main memory and storage in battery-powered mobile computing systems. However, it is more expensive than flash memory, and thus introduces a more serious storage capacity issue for low-cost solutions. This issue is further exacerbated by the fact that existing file systems are usually designed to trade Space Utilization for performance over block-oriented storage devices. In this work, we propose a multi-grained block management strategy to improve the Space Utilization of file systems over PCM-based storage systems. By utilizing the byte-addressability and fast read/write feature of PCM, a methodology is proposed to dynamically allocate multiple sizes of blocks to fit the size of each file, so as to resolve the Space fragmentation issue with minimized Space and management overheads. The Space Utilization of file systems is analyzed with consideration of block sizes. A series of experiments was conducted to evaluate the efficacy of the proposed strategy, and the results show that the proposed strategy can significantly improve the Space Utilization of file systems.

  • NVMSA - Optimizing Space Utilization of file systems on PCM-based storage devices
    2014 IEEE Non-Volatile Memory Systems and Applications Symposium (NVMSA), 2014
    Co-Authors: Yuan-hao Chang, Tseng-yi Chen, Hsin-wen Wei, Wei-kuan Shih, Yun-jhu Chen, Zhao-rong Lai
    Abstract:

    Phase-change memory (PCM) is a promising candidate as a storage medium to resolve the performance gap between main memory and storage in battery-powered mobile computing systems. However, it is more expensive than flash memory, and thus introduces a more serious storage capacity issue in low-cost solutions. This issue is further exacerbated by the fact that existing file systems are usually designed to trade Space Utilization for performance over block-oriented storage devices. In this work, we propose a multi-grained block management scheme to optimize the Space Utilization of file systems on PCM-based storage systems. By utilizing the byte-addressability and fast read/write feature of PCM, a methodology is proposed to dynamically allocate multiple sizes of blocks to fit the size of each file, so as to resolve the Space fragmentation issue with minimized Space and management overheads. A series of experiments was conducted to evaluate the efficacy of the proposed scheme, and the results show that the proposed scheme could significantly improve the Space Utilization of file systems.

Billy Pik Lik Lau - One of the best experts on this subject based on the ideXlab platform.

  • sensor fusion for public Space Utilization monitoring in a smart city
    IEEE Internet of Things Journal, 2018
    Co-Authors: Billy Pik Lik Lau, Nipun Wijerathne, Chau Yuen
    Abstract:

    Public Space Utilization is crucial for urban developers to understand how efficient a place is being occupied in order to improve existing or future infrastructures. In a smart cities approach, implementing public Space monitoring with Internet-of-Things (IoT) sensors appear to be a viable solution. However, choice of sensors often is a challenging problem and often linked with scalability, coverage, energy consumption, accuracy, and privacy. To get the most from low cost sensor with aforementioned design in mind, we proposed data processing modules for capturing public Space Utilization with renewable wireless sensor network (RWSN) platform using pyroelectric infrared (PIR) and analog sound sensor. We first proposed a calibration process to remove false alarm of PIR sensor due to the impact of weather and environment. We then demonstrate how the sounds sensor can be processed to provide various insight of a public Space. Lastly, we fused both sensors and study a particular public Space Utilization based on one month data to unveil its usage.

  • spatial and temporal analysis of urban Space Utilization with renewable wireless sensor network
    International Conference on Big Data, 2016
    Co-Authors: Billy Pik Lik Lau, Tanmay Chaturvedi, Marakkalage Sumudu Hasala, Chau Yuen
    Abstract:

    Space Utilization are important elements for a smart city to determine how well public Space are being utilized. Such information could also provide valuable feedback to the urban developer on what are the factors that impact Space Utilization. The spatial and temporal information for Space Utilization can be studied and further analyzed to generate insights about that particular Space. In our research context, these elements are translated to part of big data and Internet of things (IoT) to eliminate the need of on site investigation. However, there are a number of challenges for large scale deployment, eg. hardware cost, computation capability, communication bandwidth, scalability, data fragmentation, and resident privacy etc. In this paper, we designed and prototype a Renewable Wireless Sensor Network (RWSN), which addressed the aforementioned challenges. Finally, analyzed results based on initial data collected is presented.

  • BDCAT - Spatial and temporal analysis of urban Space Utilization with renewable wireless sensor network
    Proceedings of the 3rd IEEE ACM International Conference on Big Data Computing Applications and Technologies, 2016
    Co-Authors: Billy Pik Lik Lau, Tanmay Chaturvedi, Marakkalage Sumudu Hasala, Chau Yuen
    Abstract:

    Space Utilization are important elements for a smart city to determine how well public Space are being utilized. Such information could also provide valuable feedback to the urban developer on what are the factors that impact Space Utilization. The spatial and temporal information for Space Utilization can be studied and further analyzed to generate insights about that particular Space. In our research context, these elements are translated to part of big data and Internet of things (IoT) to eliminate the need of on site investigation. However, there are a number of challenges for large scale deployment, eg. hardware cost, computation capability, communication bandwidth, scalability, data fragmentation, and resident privacy etc. In this paper, we designed and prototype a Renewable Wireless Sensor Network (RWSN), which addressed the aforementioned challenges. Finally, analyzed results based on initial data collected is presented.

Chaofan Zhou - One of the best experts on this subject based on the ideXlab platform.

  • spatial temporal evolution patterns of land subsidence with different situation of Space Utilization
    Natural Hazards, 2015
    Co-Authors: Beibei Chen, Huili Gong, Kunchao Lei, Mingliang Gao, Chaofan Zhou
    Abstract:

    Long-term over-exploitation of underground water, static and dynamic load is increasing year by year, which influenced the occurrence and development of regional land subsidence in Beijing, China. We used Envisat advanced synthetic aperture radar data acquired from 2003 to 2009 and PSI (persistent scatterers for SAR interferometry) and small baseline technology to estimate regional land subsidence information in Beijing, China. In different situation of Space Utilization, we chose five typical settlement areas according to classified information of land-use, multi-spectral remote sensing images and geological data. We analyzed the time-series evolution characteristics of uneven subsidence by GIS spatial analysis. The comparative analysis results suggest that for five typical settlement areas, the complex situations of Space Utilization affect the trend of uneven subsidence, the simpler Space Utilization situation (relatively fewer transport lines, construction), the smaller settlement differences and the smaller trend of the uneven subsidence.

  • Spatial–temporal evolution patterns of land subsidence with different situation of Space Utilization
    Natural Hazards, 2015
    Co-Authors: Beibei Chen, Huili Gong, Kunchao Lei, Mingliang Gao, Chaofan Zhou
    Abstract:

    Long-term over-exploitation of underground water, static and dynamic load is increasing year by year, which influenced the occurrence and development of regional land subsidence in Beijing, China. We used Envisat advanced synthetic aperture radar data acquired from 2003 to 2009 and PSI (persistent scatterers for SAR interferometry) and small baseline technology to estimate regional land subsidence information in Beijing, China. In different situation of Space Utilization, we chose five typical settlement areas according to classified information of land-use, multi-spectral remote sensing images and geological data. We analyzed the time-series evolution characteristics of uneven subsidence by GIS spatial analysis. The comparative analysis results suggest that for five typical settlement areas, the complex situations of Space Utilization affect the trend of uneven subsidence, the simpler Space Utilization situation (relatively fewer transport lines, construction), the smaller settlement differences and the smaller trend of the uneven subsidence.

Timothy A. Hall - One of the best experts on this subject based on the ideXlab platform.

  • WCNC - Analytical Modeling of White Space Utilization for a Dynamic Spectrum Access System
    2019 IEEE Wireless Communications and Networking Conference (WCNC), 2019
    Co-Authors: Charles Hagwood, Anirudha Sahoo, Timothy A. Hall
    Abstract:

    Dynamic Spectrum Access (DSA) promises to be a shared spectrum technology that can alleviate the artificial spectrum crunch created by the static allocation of spectrum. There have been many studies on DSA systems in the literature. However, most of them are analyzed using simulation studies rather than analytical modeling. Analytical models are useful in evaluating performance of such systems quickly and easily. In this paper, we present an analytical model of an opportunistic DSA system. Using an alternating renewal process to represent primary user traffic of the DSA system and applying theory from survival analysis and stochastic process, we derive an expression to compute the white Space Utilization (WSU) of a DSA system for a general distribution of idle durations of primary traffic. Taking the exponential distribution as an example, we validate our analytical model by comparing its results to results obtained from two simulation experiments. One experiment uses idle durations generated from pseudorandom variates and the other uses data collected from a real Long-Term Evolution (LTE) system whose idle duration distribution is approximately exponential. Our analytical WSU results match closely with those from the first experiment and match reasonably well with those obtained from the second experiment.