App Store Analysis studies information about applications obtained from app stores. App stores provide a wealth of information derived from users that would not exist had the applications been distributed via previous software deployment methods. App Store Analysis combines this non-technical information with technical information to learn trends and behaviours within these forms of software repositories. Findings from App Store Analysis have a direct and actionable impact on the software teams that develop software for app stores, and have led to techniques for requirements engineering, release planning, software design, security and testing. This survey describes and compares the areas of research that have been explored thus far, drawing out common aspects, trends and directions future research should take to address open problems and challenges.

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A Survey of App Store Analysis for Software Engineering

Geospatial Big Data

From the leading minds in the field, Distributed and Cloud Computing is the first modern, up-to-date distributed systems textbook Starting with an overview of modern distributed models, the book exposes the design principles, systems architecture, and innovative applications of parallel, distributed, and cloud computing systems It will teach you how to create high-performance, scalable, reliable systems, providing comprehensive coverage of distributed and cloud computing, including: Facilitating management, debugging, migration, and disaster recovery through virtualization Clustered systems for research or ecommerce applications Designing systems as web services Social networking systems using peer-to-peer computing Principles of cloud computing using examples from open-source and commercial applications Using examples from open-source and commercial vendors, the text describes cloud-based systems for research, e-commerce, social networking and more Complete coverage of modern distributed computing technology including clusters, the grid, service-oriented architecture, massively parallel processors, peer-to-peer networking, and cloud computing Includes case studies from the leading distributed computing vendors: Amazon, Microsoft, Google, and more Designed to meet the needs of students taking a distributed systems course, each chapter includes exercises and further reading, with lecture slides and solutions available online

Distributed and Cloud Computing: From Parallel Processing to the Internet of Things

A systematic literature review

In this paper, a new probabilistic method for image enhancement is presented based on a simultaneous estimation of illumination and reflectance in the linear domain We show that the linear domain model can better represent prior information for better estimation of reflectance and illumination than the logarithmic domain A maximum a posteriori (MAP) formulation is employed with priors of both illumination and reflectance To estimate illumination and reflectance effectively, an alternating direction method of multipliers is adopted to solve the MAP problem The experimental results show the satisfactory performance of the proposed method to obtain reflectance and illumination with visually pleasing enhanced results and a promising convergence rate Compared with other testing methods, the proposed method yields comparable or better results on both subjective and objective assessments

A Probabilistic Method for Image Enhancement With Simultaneous Illumination and Reflectance Estimation

Although snoop-based coherence protocols provide fast cache-to-cache transfers with a simple and robust coherence mechanism, scaling the protocols has been difficult due to the overheads of broadcast snooping. In this paper, we propose a coherence filtering technique called subspace snooping, which stores the potential sharers of each memory page in the page table entry. By using the sharer information in the page table entry, coherence transactions for a page generate snoop requests only to the subset of nodes in the system (subspace). However, the coherence subspace of a page may evolve, as the phases of applications may change or the operating system may migrate threads to different nodes. To adjust subspaces dynamically, subspace snooping supports a shrinking mechanism, which removes obsolete nodes from subspaces. Subspace snooping can be integrated to any type of coherence protocols and network topologies. As subspace snooping guarantees that a subspace always contains the precise sharers of a page, it does not restrict the designs of coherence protocols and networks. We evaluate subspace snooping with Token Coherence on un-ordered mesh networks. For scientific and server applications on a 16-core system, subspace snooping reduces 44% of snoops on average.

/pdf/subspace-snooping-filtering-snoops-with-operating-system-59fnf2lzeq.pdf

Subspace snooping: filtering snoops with operating system support

In this paper, we present a new tone mapping technique for high dynamic range images based on the retinex theory. Our algorithm consists of two steps, global adaptation and local adaptation of the human visual system. In the local adaptation process, the Gaussian filter of the retinex algorithms is substituted with a guided filter to reduce halo artifacts. To guarantee good rendition and dynamic range compression, we propose a contrast enhancement factor based on the luminance values of the scene. In addition, an adaptive nonlinearity offset is introduced to deal with the strength of the logarithm function's nonlinearity. Experiments show that our algorithm provides satisfactory results while preserving details and reducing halo artifacts.

/pdf/adaptive-local-tone-mapping-based-on-retinex-for-high-hnqqer07ip.pdf

Adaptive local tone mapping based on retinex for high dynamic range images

As users are interacting with a large of mobile apps under various usage contexts, user involvements in an app design process has become a critical issue. Despite this fact, existing apps or app store platforms only provide a limited form of user involvements such as posting app reviews and sending email reports. While building a unified platform for facilitating user involvements with various apps is our ultimate goal, we present our preliminary work on handling developers' information overload attributed to a large number of app comments. To address this issue, we first perform a simple content analysis on app reviews from the developer's standpoint. We then propose an algorithm that automatically identifies informative reviews reflecting user involvements. The preliminary evaluation results document the efficiency of our algorithm.

/pdf/facilitating-developer-user-interactions-with-mobile-app-388psg7l8v.pdf

Facilitating developer-user interactions with mobile app review digests

The physical memory capacity of servers is expected to increase drastically with the deployment of the forthcoming non-volatile memory technologies. This is a welcomed improvement for the emerging data-intensive applications. For such servers to be cost-effective, nonetheless, we must cost-effectively increase compute throughput and memory bandwidth commensurate with the increase in memory capacity without compromising the application readiness. Tackling this challenge, we present Memory Channel Network (MCN) architecture in this paper. Specifically, first, we propose an MCN DIMM, an extension of a buffered DIMM where a small but capable processor called MCN processor is integrated with a buffer device on the DIMM for near-memory processing. Second, we implement device drivers to give the host and MCN processors in a server an illusion that they are independent heterogeneous nodes connected through an Ethernet link. These allow the host and MCN processors in a server to run a given data-intensive application together based on popular distributed computing frameworks such as MPI and Spark without any change in the host processor hardware and its application software, while offering the benefits of high-bandwidth and low-latency communication between the host and MCN processors over the memory channels. As such, MCN can serve as an application-transparent framework which can seamlessly unify the near-memory processing within a server and the distributed computing across such servers for data-intensive applications. Our simulation running the full software stack shows that a server with 8 MCN DIMMs offers 4.56 x higher throughput and consume 47.5% less energy than a cluster with 9 conventional nodes connected through Ethernet links, as it facilitates up to 8.17 x higher aggregate DRAM bandwidth utilization. Lastly, we demonstrate the feasibility of MCN with an IBM POWER8 system and an experimental buffered DIMM.

Application-transparent near-memory processing architecture with memory channel network

When analyzing a distributed computer system, we often observe that the complex interplay among processor, node, and network sub-systems can profoundly affect the performance and power efficiency of the distributed computer system. Therefore, to effectively cross-optimize hardware and software components of a distributed computer system, we need a full-system simulation infrastructure that can precisely capture the complex interplay. Responding to the aforementioned need, we present dist-gem5, a flexible, detailed, and open-source full-system simulation infrastructure that can model and simulate a distributed computer system using multiple simulation hosts. Then we validate dist-gem5 against a physical cluster and show that the latency and bandwidth of the simulated network sub-system are within 18% of the physical one. Compared with the single threaded and parallel versions of gem5, dist-gem5 speeds up the simulation of a 63-node computer cluster by 83.1x and 12.8x, respectively.

Daehoon Kim

Papers

Subspace snooping: filtering snoops with operating system support

Adaptive local tone mapping based on retinex for high dynamic range images

Facilitating developer-user interactions with mobile app review digests

Application-transparent near-memory processing architecture with memory channel network

dist-gem5: Distributed simulation of computer clusters