8963340
Understanding and Aiding Code Evolution by Inferring Change Patterns
Evolution continues to play an ever-increasing role in software engineering. Although changing a program is the core of software evolution, program change patterns have not been considered as a first class entity in most classic studies of software evolution. Past empirical studies of software evolution primarily relied on quantitative and statistical analyses of a program over time, but did not focus on semantic and qualitative change patterns of a program. We hypothesize that by treating change patterns as first class entities we can better understand software evolution and also aid programmers in changing software. Our goal is to infer clone evolution patterns from a set of program versions stored in a source code repository. We defined a set of common clone evolution patterns based on our insights from the copy and paste study.
1475409
An ethnographic study of copy and paste programming practices in OOPL
Although programmers frequently copy and paste code when they develop software, implications of common copy and paste (C&P) usage patterns have not been studied previously. We have conducted an ethnographic study in order to understand programmers' C&P programming practices and discover opportunities to assist common C&P usage patterns. We observed programmers using an instrumented Eclipse IDE and then analyzed why and how they use C&P operations. Based on our analysis, we constructed a taxonomy of C&P usage patterns. This paper presents our taxonomy of C&P usage patterns and discusses our insights with examples drawn from our observations. From our insights, we propose a set of tools that both can reduce software maintenance problems incurred by C&P and can better support the intents of commonly used C&P scenarios.
63258
A doubly distributed genetic algorithm for network coding
We present a genetic algorithm which is distributed in two novel ways: along genotype and temporal axes. Our algorithm first distributes, for every member of the population, a subset of the genotype to each network node, rather thana subset of the population to each. This genotype distribution is shown to offer a significant gain in running time. Then, for efficient use of the computational resources in the network, our algorithm divides the candidate solutions intopipelined sets and thus the distribution is in the temporal domain, rather that in the spatial domain. This temporal distribution may lead to temporal inconsistency in selection and replacement, however our experiments yield better efficiency in terms of the time to convergence without incurring significant penalties.
38612898
Transient behaviors of TCP-friendly congestion control protocols
We investigate the fairness, smoothness, responsiveness, and aggressiveness of TCP and three representative TCP-friendly congestion control protocols: GAIMD, TFRC, and TEAR. The properties are evaluated both analytically and via simulation by studying protocol responses to three network environment changes. The first environment change is the inherent fluctuations in a stationary network environment. Under this scenario, we consider three types of sending rate variations: smoothness, short-term fairness, and long-term fairness. For a stationary environment, we observe that smoothness and fairness are positively correlated. We derive an analytical expression for the sending rate coefficient of variation for each of the four protocols. These analytical results match well with experimental results. The other two environment changes we study are a step increase of network congestion and a step increase of available bandwidth. Protocol responses to these changes reflect their responsiveness and aggressiveness, respectively.
47477578
DMKB : A Defense Mechanism Knowledge Base
The major cause of the internet incidents is the vulnerability, which is usually exploited by human attackers or worm virus. Thus the implementation of database on vulnerability is most valuable. If vulnerability is found newly, its information can be included in this database. The contemporary vulnerability databases, however, show weakness in describing countermeasures, although they are practically useful in removing or avoiding vulnerability. This comes from the lack of the analysis process on both semantics and patterns for countermeasures. In this paper, we defined the countermeasures in view of defense mechanism and suggested their representation schemes. In semantics, defense mechanisms can be classified into prevention, detection, recovery and tolerance. And they can be expressed in patterns as the composition of aim, condition, and action. Considering these features, we implemented a knowledge base on defense mechanism – DMKB. By using DMKB, users can get almost whole knowledge with keyword searching under GUI. Our DMKB can be utilized in automatic security testing and management for a given system.
6738575
Agent-oriented software modeling
Due to the increased applications of agents, agent-oriented software becomes large and complex. To support systematic developments of such software, the agent-oriented software development methodology needs to be developed. This paper focuses on the modeling phase of agent-oriented software development. For agent-oriented software modeling, the Agent Elicitation method, Intra and Inter Agent modeling method are proposed. Agent Elicitation shows how to extract agents from classes in the real world. Modeling methods of agent's characteristics-Goal, Belief, Plan and Capability-are proposed for Intra Agent modeling. Methods of agent's mobility and communication in multiagent systems are proposed for Inter Agent modeling.
46306635
A Blind Watermarking for 3-D Dynamic Mesh Model Using Distribution of Temporal Wavelet Coefficients
In this paper, we present a watermarking method for 3-D mesh sequences with a fixed connectivity. The main idea is to transform each coordinate of vertex with the identical connectivity index along temporal axis using wavelet transform and modify the distribution of wavelet coefficients in temporally high (or middle)-frequency frames according to watermark bit to be embedded. Due to the use of the distribution, our method can retrieve the hidden watermark without any information about original mesh sequences in the process of watermark detection. To increase the watermark capacity, all vertices are divided into groups, namely bins, using the distribution of scaling coefficients in low-frequency frames. As the vertices with the identical connectivity index over whole frames belong to one bin, their wavelet coefficients are also assigned into the same bin. Then, the watermark is embedded into each axis of the wavelet coefficients. Through simulations we show that the proposed is fairly robust against various attacks that are probably concerned in copyright protection of 3-D mesh sequences.