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An acyclic edge coloring of a graph G is a proper edge coloring such that no bichromatic cycles are produced. The acyclic chromatic index a^'(G) of G is the smallest integer k such that G has an acyclic edge coloring using k colors. Fiamcik (1978) [9] and later Alon et al. (2001) [2] conjectured that a^'(G)@?@D+2 for any simple graph G with maximum degree @D. In this paper, we confirm this conjecture for planar graphs without 5-cycles.

An acyclic edge coloring of a graph G is a proper edge coloring such that no bichromatic cycles are produced. The acyclic chromatic index a′(G) of G is the smallest integer k such that G has an acyclic edge coloring using k colors. Fiamcik (Math. Slovaca 28:139–145, 1978) and later Alon, Sudakov and Zaks (J. Graph Theory 37:157–167, 2001) conjectured that a′(G)≤Δ+2 for any simple graph G with maximum degree Δ. In this paper, we confirm this conjecture for planar graphs G with Δ≠4 and without 4-cycles.

A proper vertex coloring of a graph G is linear if the graph induced by the vertices of any two color classes is the union of vertex-disjoint paths. The linear chromatic number lc(G) of G is the smallest number of colors in a linear coloring of G. In this paper, we prove that if G is a planar graph without 4-cycles, then lc $${(G)\le \lceil \frac {\Delta}2\rceil+8}$$ , where Δ denotes the maximum degree of G.

The adjacent vertex-distinguishing chromatic index χ a ′ ( G ) of a graph G is the smallest integer k for which G admits a proper edge k -coloring such that any pair of adjacent vertices are incident to distinct sets of colors. In this paper, we prove that if G is a K 4 -minor free graph, without isolated edges, and with maximum degree Δ ≥ 4 , then Δ ≤ χ a ′ ( G ) ≤ Δ + 1 ; when Δ ≥ 5 , χ a ′ ( G ) = Δ if and only if G contains no adjacent vertices of maximum degree.

An adjacent vertex distinguishing edge-coloring of a graph G is a proper edge coloring of G such that any pair of adjacent vertices are incident to distinct sets of colors. The minimum number of colors required for an adjacent vertex distinguishing edge-coloring of G is denoted by χ′ a (G). Let $\mathop{\mathrm{mad}}(G)$ and Δ denote the maximum average degree and the maximum degree of a graph G, respectively. In this paper, we prove the following results: (1) If $\mathop{\mathrm{mad}}(G)

An adjacent vertex distinguishing total coloring of a graph G is a proper total coloring of G such that any pair of adjacent vertices are incident to distinct sets of colors. The minimum number of colors required for an adjacent vertex distinguishing total coloring of G is denoted by χ″a(G). In this paper, we characterize completely the adjacent vertex distinguishing total chromatic number of outerplanar graphs.

The mechanism of sevoflurane preconditioning-induced neuroprotection is poorly understood. This study was aimed at identifying microRNAs (miRNAs) involved in the protective effect of sevoflurane preconditioning against hypoxic injury using the miRCURYTM LNA Array. The screened differentially expressed miRNAs were further validated using qRT-PCR. Finally, after transfection of miRNA (miR-101a or miR-34b) mimics or inhibitor, MTT and flow cytometry assays were used to evaluate cell survival and apoptosis in sevoflurane preconditioning. qRT-PCR confirmed the changes in expression of differentially expressed miRNAs that were screened by the microarray: down-regulation of rno-miR-101a, rno-miR-106b, and rno-miR-294 and up-regulation of rno-miR-883, rno-miR-16, and rno-miR-34b. MiR-101a and miR-34b were the most differentially expressed miRNAs. Sevoflurane preconditioning-inhibited apoptosis and preconditioning-enhanced cell viability of PC12 cells were significantly attenuated by transfection of miR-101a mimetic or miR-34b inhibitors, but were significantly enhanced by transfection of miR-34b mimetic. Therefore, a number of miRNAs, including miR-101a and miR-34b, might play important roles in the neuroprotection induced by sevoflurane preconditioning. Such miRNAs might provide novel targets for preventive and therapeutic strategies against cerebral ischemia-reperfusion injury.

NAC transcription factors are plant-specific and play important roles in many processes including plant development, response to biotic and abiotic stresses and hormone signaling. So far, only a few NAC genes have been identified to mediate cell death. In this study, we identified a novel NAC gene from canola (Brassica napus L.), BnaNAC103 which induces reactive oxygen species (ROS) accumulation and cell death in Nicotianabenthamiana leaves. We found that BnaNAC103 responded to multiple signalings, including cold, salicylic acid (SA) and a fungal pathogen Sclerotinia sclerotiorum. BnaNAC103 is located in the nucleus. Expression of full-length BnaNAC103, but not either the N-terminal NAC domain or C-terminal regulatory domain, was identified to induce hypersensitive response (HR)-like cell death when expressed in N. benthamiana. The cell death triggered by BnaNAC103 is preceded by accumulation of ROS, with diaminobenzidine (DAB) staining supporting this. Moreover, quantification of ion leakage and malondialdehyde (MDA) of leaf discs indicates significant cell membrane breakage and lipid peroxidation induced by BnaNAC103 expression. Taken together, our work has identified a novel NAC transcription factor gene modulating ROS level and cell death in plants.

The principle by which unmyelinated primary sensory neurons transducing thermal, itch and pain perception are specified in early development is unknown. These classes of sensory neurons diversify from a common population of late-born neurons, which initiate expression of Runt homology domain transcription factor RUNX1 and the nerve growth factor receptor TrkA. Here, we report that signals emanating from within the mouse dorsal root ganglion mediated partly by early-born neurons destined to a myelinated phenotype participate in fating late-born RUNX1+/TrkA+neurons. Inductive factors include FGFs via activation of FGF receptor 1 (FGFR1). Consistently, FGF2 is sufficient to induce expression of RUNX1, andFgfr1conditional mutant mice display deficits in fating of the common population of late-born RUNX1+/TrkA+neurons that develop into unmyelinated neurons. Thus, the distinct lineages of sensory neurons are acquired in response to increasing FGF levels provided by a rising number of born neurons.

Neurotrophins are key players of neural development by controlling cell death programs. However, the signaling pathways that mediate their selective responses in different populations of neurons remain unclear. In the mammalian cochlea, sensory neurons differentiate perinatally into type I and II populations both expressing TrkB and TrkC, which bind respectively brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3). How these two neuronal populations respond differentially to these two neurotrophins remains unknown. Here, we report in rat the segregation of the nuclear factor-κB (NFκB) subunit p65 specifically within the type II population postnatally. Using dissociated cultures of embryonic and postnatal spiral ganglion neurons, we observed a specific requirement of NFκB for BDNF but not NT3-dependent neuronal survival during a particular postnatal time window that corresponds to a period of neuronal cell death and hair cell innervation refinement in the developing cochlea. Consistently, postnatal p65 knockout mice showed a specific decreased number in type II spiral ganglion neurons. Taken together, these results identify NFκB as a type II neuron-specific factor that participates in the selective survival effects of BDNF and NT3 signaling on developing spiral ganglion neurons.

The formation of functional connectivity in the nervous system is governed by axon guidance that instructs nerve growth and branching during development, implying a similarity between neuronal subtypes in terms of nerve extension. We demonstrate the molecular mechanism of another layer of complexity in vertebrates by defining a transcriptional program underlying growth differences between positionally different neurons. The rate of axon extension of the early subset of embryonic dorsal root ganglion sensory neurons is encoded in neurons at different axial levels. This code is determined by a segmental pattern of axial levels of Runx family transcription factor Runx3. Runx3 in turn determines transcription levels of genes encoding cytoskeletal proteins involved in axon extension, including Rock1 and Rock2 which have ongoing activities determining axon growth in early sensory neurons and blocking Rock activity reverses axon extension deficits of Runx3(-/-) neurons. Thus, Runx3 acts to regulate positional differences in axon extension properties apparently without affecting nerve guidance and branching, a principle that could be relevant to other parts of the nervous system.

An acyclic edge coloring of a graph $G$ is a proper edge coloring such that no bichromatic cycles are produced. The acyclic chromatic index $a'(G)$ of $G$ is the smallest integer $k$ such that $G$ has an acyclic edge coloring using $k$ colors. It was conjectured that $a'(G)\le \Delta+2$ for any simple graph $G$ with maximum degree $\Delta$. In this paper, we prove that if $G$ is a planar graph, then $a'(G)\leq\Delta +7$. This improves a result by Basavaraju et al. [{\em Acyclic edge-coloring of planar graphs}, SIAM J. Discrete Math., 25 (2011), pp. 463-478], which says that every planar graph $G$ satisfies $a'(G)\leq\Delta +12$., Comment: 23 pages, 1 figures

It is important for any operational software system to be able to monitor itself for compliance with its specifications and to diagnose what went wrong in case of failures. In our previous work we presented a monitoring and diagnostic framework for verifying that a system is in compliance with its requirements [23, 24]. In this paper we extend our framework so that it can verify whether a software system complies with its other (and lower-level) specifications, namely its statechart. The framework monitors the software system's runtime behavior and identifies any failures that occur. We illustrate our framework with a medium-sized publicly available case study (an ATM simulation) and evaluate its performance through a series of experiments. The results demonstrate that our framework is scalable to industrial-size software systems with medium to large statecharts.

High variability software systems can deliver their functionalities in multiple ways by reconfiguring their components. High variability has become important because of current trends towards software systems that come in product families, offer high levels of personalization, and fit well within a service-oriented architecture. The purpose of our research is to propose a framework that exploits such variability to allow a software system to self-repair in cases of failure. We propose an autonomic architecture that consists of monitoring, diagnosis, reconfiguration and execution components. This architecture uses requirements models as a basis for monitoring, diagnosis, and reconfiguration. We illustrate our proposal with a medium-sized publicly available case study (an Automated Teller Machine (ATM) simulation), and evaluate its performance through a series of experiments. Our experimental results demonstrate that it is feasible to scale our approach to software systems with medium-size requirements.

Requirements evolution is a research problem that has received little attention hitherto, but deserves much more. For systems to survive in a volatile world, where business needs, government regulations and computing platforms keep changing, software systems must evolve too in order to survive. We discuss the state-of-the-art for research on the topic, and predict some of the research problems that will need to be addressed in the next decade. We conclude with a concrete proposal for a run-time monitoring framework based on (requirements) goal models.

An adjacent vertex distinguishing total coloring of a graph $G$ is a proper total coloring of $G$ such that any pair of adjacent vertices are incident to distinct sets of colors. The minimum number of colors required for an adjacent vertex distinguishing total coloring of $G$ is denoted by $\chi''_{a}(G)$. Let mad$(G)$ and $\Delta(G)$ denote the maximum average degree and the maximum degree of a graph $G$, respectively. In this paper, we prove the following results: (1) If $G$ is a graph with mad$(G)\lt 3$ and $\Delta(G)\ge 5$, then $\Delta(G)+1\le \chi''_{a}(G)\le \Delta(G)+2$, and $\chi''_{a}(G)=\Delta(G)+2$ if and only if $G$ contains two adjacent vertices of maximum degree; (2) If $G$ is a graph with mad$(G)\lt 3$ and $\Delta(G)\le 4$, then $\chi''_{a}(G)\le 6$; (3) If $G$ is a graph with mad$(G)\lt \frac 83$ and $\Delta(G)\le 3$, then $\chi''_{a}(G)\le 5$.

Monitoring the satisfaction of software requirements and diagnosing what went wrong in case of failure is a hard problem that has received little attention in the Software and Requirement Engineering literature. To address this problem, we propose a framework adapted from artificial intelligence theories of action and diagnosis. Specifically, the framework monitors the satisfaction of software requirements and generates log data at a level of granularity that can be tuned adaptively at runtime depending on monitored feedback. When errors are found, the framework diagnoses the denial of the requirements and identifies problematic components. To support diagnostic reasoning, we transform the diagnostic problem into apropositional satisfiability (SAT) problem that can be solved by existing SAT solvers. We preprocess log data into a compact propositional encoding that better scales with problem size. The proposed theoretical framework has been implemented as a diagnosing component that will return sound and complete diagnoses accounting for observed aberrant system behaviors. Our solution is illustrated with two medium-sized publicly available case studies: a Web-based email client and an ATM simulation. Our experimental results demonstrate the feasibility of scaling our approach to medium-size software systems

Reverse engineering aims at extracting many kinds of information from existing software and using this information for system renovation and program understanding. The goal of this full day WCRE'05 workshop is to identify methods and techniques for Reverse Engineering from software to Requirements (RETR).

We investigate the personalization capabilities of common personal software systems. We use a typical e-mail client as an example of such a system, and examine the configuration screens it offers to its users. We discover that each configuration value reflects each of the ways with which the user goals can be satisfied. Thus, we construct a goal model in which alternative ways for satisfying high level goals are matched with alternative system configurations. This way, automatic configuration of the system by reasoning about the overlaying goal model can be achieved. We find that the vast majority of the configuration options that refer to system functionality can be configured using this method, facilitating thereby the personalization tasks for users with no technical background, and ensuring, at the same time, consistency and meaningfulness in the configuration result.

The Web-services stack of standards is designed to support the reuse and interoperation of software components on the Web. A critical step, to that end, is service discovery, i.e., the identification of existing Web services that can potentially be used in the context of a new Web application. UDDI, the standard API for publishing Web-services specifications, provides a simple browsing-by-business-category mechanism for developers to review and select published services. In our work, we have developed a flexible service discovery method, for identifying potentially useful services and assessing their relevance to the task at hand. Given a textual description of the desired service, a traditional information-retrieval method is used to identify the most similar service description files, and to order them according to their similarity. Next, given this set of likely candidates and a (potentially partial) specification of the desired service behavior, a structure-matching step further refines and assesses the quality of the candidate service set. In this paper, we describe and experimentally evaluate our Web-service discovery process.

The web-services stack of standards is designed to support the reuse and interoperation of software components on the web. A critical step in the process of developing applications based on web services is service discovery, i.e., the identification of existing web services that can potentially be used in the context of a new web application. UDDI, the standard API for publishing web-services specifications, provides a simple browsing-by-business-category mechanism for developers to review and select published services. To support programmatic service discovery, we have developed a suite of methods that utilizes both the semantics of the identifiers of WSDL descriptions and the structure of their operations, messages and data types to assess the similarity of two WSDL files. Given only a textual description of the desired service, a semantic information-retrieval method can be used to identify and order the most similar service-description files. This step assesses the similarity of the provided description of the desired service with the available services. If a (potentially partial) specification of the desired service behavior is also available, this set of likely candidates can be further refined by a semantic structure-matching step assessing the structural similarity of the desired vs. the retrieved services and the semantic similarity of their identifier. In this paper, we describe and experimentally evaluate our suite of service-similarity assessment methods.

A highly efficient broadband terahertz absorber is designed, fabricated, and experimentally as well as theoretically evaluated. The absorber comprises a heavily doped silicon substrate and a well-designed two-dimensional grating. Due to the destructive interference of waves and diffraction, the absorber can achieve over 95% absorption in a broad frequency range from 1 to 2 THz and for angles of incidence from 0° to 60°. Such a terahertz absorber is also polarization-independent due to its symmetrical structure. This omnidirectional and broadband absorber have potential applications in anti-reflection coatings, imaging systems, and so on.

A plane graph G is entirely k-choosable if, for every list L of colors satisfying L(x) = k for x ∈ V(G) ∪ E(G) ∪ F(G), there exists a coloring which assigns to each vertex, each edge and each face a color from its list so that any adjacent or incident elements receive different colors. In this paper, we show that every plane graph G with maximum degree Δ ≤ 5 is entirely (Δ + 5)-choosable.

An acyclic list edge coloring of a graph G is a proper list edge coloring such that no bichromatic cycles are produced. In this paper, we prove that an outerplanar graph G with maximum degree Δ ≥ 5 has the acyclic list edge chromatic number equal to Δ .

A reverse engineering process aims at reconstructing high-level abstractions from source code. This paper presents a novel reverse engineering methodology for recovering stakeholder goal models from both structured and unstructured legacy code. The methodology consists of the following major steps: 1) Refactoring source code by extracting methods based on comments; 2) Converting the refactored code into an abstract structured program through statechart refactoring and hammock graph construction; 3) Extracting a goal model from the structured program's abstract syntax tree; 4) Identifying nonfunctional requirements and derive soft goals based on the traceability between the code and the goal model. To illustrate this requirements recovery process, we refactor stakeholder goal models from two legacy software code bases: an unstructured Web-based email in PHP (SquirrelMail) and a structured email client system in Java (Columba).