Big data processing frameworks such as Hadoop have been widely adopted in the past few years. However, the security issues in such large scale systems have not been well studied yet. While most of the prior work is focused on the data privacy and protection, this paper investigates a potential attack from a compromised internal node against the overall system performance. We explore the vulnerabilities of the existing Hadoop system, and develop an effective attack launched from the compromised node that can significantly degrade the data processing performance of the cluster without being detected and blacklisted for job execution. In addition, we present a mitigation scheme that protects a Hadoop system from such attack. We conduct experiments on real systems, and the results show that this attack greatly slows down the job executions in the native Hadoop system even with some basic defense mechanisms. Our mitigation scheme, while causing a minor overhead in normal circumstances, can keep the whole cluster running efficiently under this attack from the compromised internal node.
Smartphones play an important role in mobile social networks. This paper presents a Mobile Message Board (MMB) system for smartphone users to post and share messages in a cer- tain area. Our system is built upon ad-hoc communication model, and allows the users to browse the nearby information without pre-registration with any servers. Our algorithm design focuses on the message management on each phone considering its own schedule of turning the wireless device on and off. We present algorithms for two different cases to maximize the availability of the messages. Furthermore, we have implemented our solutions on commercial smartphones, and conducted experiments and simulation for evaluation. The results are supportive and shows that the MMB system is efficient and effective for location-based message dissemination.
This paper investigates the routing protocols in smartphone-based mobile Ad-Hoc networks. We introduce a new dual radio communication model, where a long-range, low cost, and low rate radio is integrated into smartphones to assist regular radio interfaces such as WiFi and Bluetooth. We propose to use the long-range radio to carry out small management data packets to improve the routing protocols. Specifically, we develop new schemes to improve the efficiency of the path establishment and path recovery process in the on-demand Ad- Hoc routing protocols. We have prototyped our solution LAAR on Android phones and evaluated the performance with small scale experiments and large scale simulation implemented on NS2. The results show that LAAR significantly improves the performance.
MapReduce has become a popular data processing framework in the past few years. With the rise of cloud computing and the high demand of big data processing, we envision that more and more users will launch a MapReduce cluster to process a large volume of data in various applications. Scheduling algorithm is crucial to the performance of a MapReduce cluster, especially when the cluster is concurrently executing a batch of MapReduce jobs. However, the scheduling problem in MapReduce is different from the traditional job scheduling problem as the reduce phase usually starts before the map phase is finished to "shuffle" the intermediate data. This paper develops a new strategy, named OMO, which particularly aims to optimize the overlap between the map and reduce phases. Our solution includes two new techniques, lazy start of reduce tasks and batch finish of map tasks, which catch the characteristics of the overlap in a MapReduce process and achieve a good alignment of the two phases. We have implemented OMO on Hadoop system and evaluated the performance with extensive experiments. The results show that OMO's performance is superior in terms of total completion length (i.e., makespan) of a batch of jobs.
This paper investigates the routing protocol in smartphone-based mobile Ad-Hoc networks. We introduce a new dual radio communication model, where a long-range, low cost, and low rate radio is integrated into smartphones to assist regular radio interfaces such as WiFi and Bluetooth. We propose to use the long-range radio to carry out small management data packets to improve the routing protocols. Specifically, we develop new schemes built on the long-range radio to improve the efficiency of the path establishment process in the existing on-demand Ad- Hoc routing protocols. We have prototyped our solution LAAR on Android phones and evaluated the performance with small scale experiments and large scale simulation implemented on NS2. The results show that LAAR significantly improve the performance in terms of the overhead and the number of messages transferred in the network.
This paper studies the video buffer control for streaming video data to mobile devices. We target on the design challenge when the wireless link quality is dynamic due to the the environmental factors or user mobility. We develop a Dynamic and Agile buffor- control scheme, called DAB, that adaptively adjusts the video buffer size based on the measurements of the signal strength (RSSI) and accelerometer on the smartphone. Our goal is to keep a smooth playback while deliver as little data as possible to the end-user in order to save bandwidth cost. We have implemented our solution on Android platform and evaluated it with experiments. Compared to traditional video buffer schemes, our solution DAB significantly improves the performance in terms of the quality of playback and the buffer efficency.
Smartphones have become more and more popular in the past few years. Motivated by the fact that location plays an extremely important role in mobile applications, this paper develops an efficient local message dissemination system PASA based on a new communication model called passive broadcast. It is based on the method of overloading device names described in MDSRoB  and Bluejacking . In this new model, each node does not maintain connection state and data delivery is initialized by a receiver via a ‘scan’ operation. The representative carriers of passive broadcast include Bluetooth and WiFi-Direct, both of which define a mandatary ‘peer discovery’ scan function. Passive broadcast features negligible cost for establishing and maintaining direct links and is extremely suitable for short message dissemination in the proximity. In this paper, we present PASA with complete protocols and in-depth analysis for optimization. We have prototyped our solution on commercial phones and evaluated it with comprehensive experiments and simulation.
Hadoop is an emerging framework for parallel big data processing. While becoming popular, Hadoop is too complex for regular users to fully understand all the system parameters and tune them appropriately. Especially when processing a batch of jobs, default Hadoop setting may cause inefficient resource utilization and unnecessarily prolong the execution time. This paper considers an extremely important setting of slot configuration which by default is fixed and static. We proposed an enhanced Hadoop system called FRESH which can derive the best slot setting, dynamically configure slots, and appropriately assign tasks to the available slots. The experimental results show that when serving a batch of MapReduce jobs, FRESH significantly improves the makespan as well as the fairness among jobs.
This paper targets the application of cloud storage management for mobile devices. Because of the limit of bandwidth and other resources, most existing cloud storage apps for smartphones do not keep local copies of files. This efficient design, however, limits the application capacities. In this paper, our goal is to extend the available file operations for cloud storage service to better serve smartphone users. We develop Skyfiles, an efficient and secure file management system that supports more advance file operations. Our basic idea is to utilize cloud instance to assist file operations. Particularly, Skyfiles supports download, compress, encrypt, convert operations, and file transfer between two smartphone users’ cloud storage spaces. In addition, we design protocol for users to share their idle instances. All file operations designed in Skyfiles can be efficiently and securely accomplished with a self-created instance or shared instance.
The emergence of powerful mobile devices has allowed users to publish more contents in the Internet in recent years. The existing Internet architecture cannot cope with such exponential growth in users published contents. Content-centric networks have been proposed recently to allow future Internet to be data-centric rather than network centric. Several content centric networking approaches have been proposed, but most of them assume that users know the unique identifiers of the contents that are of interests to them. SECON  proposed a content centric mobile network solution that provides keywordbased retrievals. However, the authors do not provide detailed description on how their solution can be made scalable. In this paper, we propose two scalable solutions for keywordbased retrievals in content centric networks. Our preliminary simulation results indicate that our solutions are scalable.