Performance bugs are programming errors that slow down program execution. While existing techniques can detect various types of performance bugs, a crucial and practical aspect of performance bugs has not received the attention it deserves: how likely are developers to fix a performance bug? In practice, fixing a performance bug can have both benefits and drawbacks, and developers fix a performance bug only when the benefits outweigh the drawbacks. Unfortunately, for many performance bugs, the benefits and drawbacks are difficult to assess accurately. This paper presents CARAMEL, a novel static technique that detects and fixes performance bugs that have non-intrusive fixes likely to be adopted by developers. Each performance bug detected by CARAMEL is associated with a loop and a condition. When the condition becomes true during the loop execution, all the remaining computation performed by the loop is wasted. Developers typically fix such performance bugs because these bugs waste computation in loops and have non-intrusive fixes: when some condition becomes true dynamically, just break out of the loop. Given a program, CARAMEL detects such bugs statically and gives developers a potential source-level fix for each bug. We evaluate CARAMEL on real-world applications, including 11 popular Java applications (e.g., Groovy, Log4J, Lucene, Struts, Tomcat, etc) and 4 widely used C/C++ applications (Chromium, GCC, Mozilla, and My SQL). CARAMEL finds 61 new performance bugs in the Java applications and 89 new performance bugs in the C/C++ applications. Based on our bug reports, developers so far have fixed 51 and 65 performance bugs in the Java and C/C++ applications, respectively. Most of the remaining bugs are still under consideration by developers.

Swarm Intelligence (SI) is a nature-inspired emergent artificial intelligence. They are often inspired by the phenomena in nature. Many proposed algorithms are focused on designing new update mechanisms with formulae and equations to emerge new solutions. Despite the techniques used in an algorithm being the key factor of the whole system, the evaluation of candidate solutions also plays an important role. In this paper, the proposed algorithm Macroscopic Indeterminacy Swarm Optimization (MISO) presents a new search scheme with indeterminate moment of evaluation. Here, we perform an experiment based on public benchmark functions. The results produced by MISO, Differential Evolution (DE) with various settings, Artificial Bee Colony (ABC), Simplified Swarm Optimization (SSO), and Particle Swarm Optimization (PSO) have been compared. The result shows MISO can achieve similar or even better performance than other algorithms.

This research extends our previous work on decision makers with methodology to optimize the design of a strategy for constructing Radio Frequency Identification (RFID). RFID technology is an automatic identification system through radio frequency for transferring data. Before deploying RFID system, one of the challenging problems is RFID network planning (RNP). The RNP problem must be solved to operate the large-scale network of readers, and need to satisfy a set of requires, such as coverage rate, economic, interference. This paper extends our previous work using soft computing technique to find the optimal positions of RFID readers based on Simplified Swarm Optimization (SSO) algorithm. Meanwhile, the fuzzy-ART and K-means models are applied to efficiently and effectively search better solutions.

Dalvik virtual machine in the Android system creates a profiling barrier between VM-space applications and Linux user-space libraries. It is difficult for existing profiling tools on the Android system to definitively identify whether a bottleneck occurred in the application level, the Linux user-space level, or the Linux kernel level. Information barriers exist between VM-space applications and Linux native analysis tools due to runtime virtual machines' dynamic memory allocation mechanism. Furthermore, traditional vertical profiling tools targeted for Java virtual machines cannot be simply applied on the Dalvik virtual machine due to its unique design. The proposed the Reconfigurable Vertical Profiling Framework bridges the information gap and streamlines the hardware-software co-design process for the Android runtime system.

Sequential and concurrency bugs are widespread in deployed software. They cause severe failures and huge financial loss during production runs. Tools that diagnose production-run failures with low overhead are needed. The state-of-the-art diagnosis techniques use software instrumentation to sample program properties at run time and use off-line statistical analysis to identify properties most correlated with failures. Although promising, these techniques suffer from high run-time overhead, which is sometimes over 100%, for concurrency-bug failure diagnosis and hence are not suitable for production-run usage.

A full system emulator, such as QEMU, can provide a versatile virtual platform for software development. However, most current system simulators do not have sufficient support for multi-processor emulations to effectively utilize the underlying parallelism presented by today's multi-core processors. In this paper, we focus on parallelizing a system emulator and implement a prototype parallel emulator based on the widely used QEMU. Using this parallel QEMU, emulating an ARM11MPCore platform on a quad-core Intel i7 machine with the SPLASH-2 benchmarks, we have achieved 3.8x speedup over the original QEMU design. We have also evaluated and compared the performance impact of two different parallelization strategies, one with minimum sharing among emulated CPU, and one with maximum sharing.

Error concealment plays an important role in robust video transmission. Recently, Chen and Leung presented an efficient data hiding-based (DH-based) approach to recover corrupted macroblocks from the intra-frame of an H.264/AVC sequence, but it suffers from the quality degradation problem. Since the quantized discrete cosine transform coefficients of an H.264/AVC sequence tend to form a Laplace distribution, we therefore propose a reversible DH-based approach for intra-frame error concealment based on this characteristic. Our design is able to achieve no quality degradation. Experimental results demonstrate that the quality of recovered video sequences obtained by our approach is indeed superior to that of the DH-based method. In addition, the quality advantage of our approach is illustrated when compared with the previous five related methods.

In demand of more computing power and less energy use, multiprocessor with power management facility emerges in embedded system design. Dynamic voltage scaling is such a facility that varies clock speed and supply voltage to save more energy. In this paper, we propose ETAHM to allocate tasks on a target multiprocessor system. In pursuit of global optimal solution, it mixes task scheduling, mapping and DVS utilization in one phase and couples ant colony optimization algorithm. Extensive experiments show ETAHM could save 22.71% more energy than CASPER (V. Kianzad et al., 2005), a state-of-the-art integrated framework that tackles the identical problem with genetic algorithm instead.