On the State of the Art of Coupling and Cohesion Measures for Service-Oriented System Design

Service-oriented computing has encountered an increasing importance for enterprises over the last years. With Web services, the major underlying technical basis is already in an advanced state. The service design area, on the other hand, still provides several research gaps such as the field of service identification and in particular the determination of an optimal granularity level for services. Granularity, assessed through coupling and cohesion considerations, is yet a rather unexplored domain when it comes to service-orientation, although several results from earlier design principles are available. In this paper we summarize the current state of the art in granularity measures and identify the implications emerging for practice and re-search. As we reveal, several existing measures for other paradigms, which might be adapted for service-orientation, are left unconsidered. Further research gaps, as the mainly missing empirical evaluation or a tighter inclusion in the development process, are also detected

An absolute calibration system for millimeter-accuracy APOLLO measurements

Lunar laser ranging provides a number of leading experimental tests of gravitation -- important in our quest to unify General Relativity and the Standard Model of physics. The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) has for years achieved median range precision at the ~2 mm level. Yet residuals in model-measurement comparisons are an order-of-magnitude larger, raising the question of whether the ranging data are not nearly as accurate as they are precise, or if the models are incomplete or ill-conditioned. This paper describes a new absolute calibration system (ACS) intended both as a tool for exposing and eliminating sources of systematic error, and also as a means to directly calibrate ranging data in-situ. The system consists of a high-repetition-rate (80 MHz) laser emitting short (< 10 ps) pulses that are locked to a cesium clock. In essence, the ACS delivers photons to the APOLLO detector at exquisitely well-defined time intervals as a "truth" input against which APOLLO's timing performance may be judged and corrected. Preliminary analysis indicates no inaccuracies in APOLLO data beyond the ~3 mm level, suggesting that historical APOLLO data are of high quality and motivating continued work on model capabilities. The ACS provides the means to deliver APOLLO data both accurate and precise below the 2 mm level.Comment: 21 pages, 10 figures, submitted to Classical and Quantum Gravit

Is BPMN the Better UML for Domain Experts? Discussion, Evaluation and Comparison - An Empirical Study

The increased demand for a more comprehensive approach to Business Process Management, amongst others, led to the development of the Business Process Modeling Notation (BPMN) as a proposed industry standard. Today, BPMN has not only become popular, it has also been adopted by the Object Management Group (OMG) as core standard to create a new business modeling framework. The OMG intentionally decided not to build upon the Unified Modeling Language (UML) and its process modeling notation – the Activity Diagram (AD) –, because BPMN was presumed to be more applicable by domain experts. Consolidated findings in this direction, however, are missing. In this paper, we present results from an em-pirical study, in which the application of BPMN and AD by domain experts was examined. Based on a comparative discus-sion of BPMN and AD, we describe the study design and highlight central outcomes which are then being evaluated in detail. This evaluation leads to an extensive comparison of the applicability of BPMN and AD based on empirical indications

A SEMI-AUTOMATED APPROACH TO SUPPORT THE ARCHITECT DURING THE GENERATION OF COMPONENT-BASED ENTERPRISE ARCHITECTURES

In today?s volatile business environments, enterprises need to be able to flexibly adapt their information systems and add new functionality quickly. Component-based enterprise architectures promise to help solving these challenges by structuring information systems landscapes into modular business components. However, the derivation of business components from conceptual models still poses research challenges as current methods do not adequately involve the architect and his/her situational preferences. In this paper, we propose an advanced method that facilitates a systematic, reflected derivation of business components. The novel contribution of this paper thereby is to show (i) how the architect can define the derivation of business components from conceptual models as a multi-criteria decision-making problem according to his/her situational preferences and (ii) how the architect can systematically verify the stability of the derivation results. We demonstrate the feasibility of the proposed method by demonstrating its implementation as part of the SeaCoAST tool and applying it to the after-sales processes of a world-wide leading automobile manufacturer

Probing the ultrafast dynamics of excitons in single semiconducting carbon nanotubes

Excitonic states govern the optical spectra of low-dimensional semiconductor nanomaterials and their dynamics are key for a wide range of applications, such as in solar energy harvesting and lighting. Semiconducting single-walled carbon nanotubes emerged as particularly rich model systems for one-dimensional nanomaterials and as such have been investigated intensively in the past. The exciton decay dynamics in nanotubes has been studied mainly by transient absorption and time-resolved photoluminescence spectroscopy. Since different transitions are monitored with these two techniques, developing a comprehensive model to reconcile different data sets, however, turned out to be a challenge and remarkably, a uniform description seems to remain elusive. In this work, we investigate the exciton decay dynamics in single carbon nanotubes using transient interferometric scattering and time-resolved photoluminescence microscopy with few-exciton detection sensitivity and formulate a unified microscopic model by combining unimolecular exciton decay and ultrafast exciton-exciton annihilation on a time-scale down to 200 fs

An Empirical Comparison of the Usability of BPMN and UML Activity Diagrams for Business Users

The widespread implementation of Business Process Management (BPM) strategies has increased the demand for an integral approach to business process modeling, in which all stakeholders can effectively participate and together shape a company’s business processes. Amongst others, this demand was a basis for the development of the Business Process Modeling Notation (BPMN) as a proposed industry standard. It does not only provide technical advantages such as a support for serviceoriented computing, but also claims to be readily usable for business users. Following this presumption, BPMN is even used by the Object Management Group (OMG). It adopted BPMN instead of the Activity Diagram (UML AD) as the core standard to create a business modeling framework. For companies, however, changing to a new process modeling language is a significant expense factor. Furthermore, consolidated findings on whether BPMN is indeed more usable for business users than UML AD are missing. In this paper, we present results from a comprehensive empirical comparison of both languages, in which we examined the application by business users during a model creation task. Results indicate that the UML AD is at least as usable as BPMN, since BPMN did neither differ significantly in effectiveness, efficiency, nor user satisfaction

On the Developer Adoption of Scrum: A New Acceptance Model for Agile Methodologies

In recent years, the agile Scrum methodology has become a popular software development approach. It significantly differs from traditional approaches as it promotes communication, self-organization, flexibility, and innovation instead of extensive planning and codified processes. While such a paradigm shift promises to better support the timely delivery of high-quality software in turbulent business environments, its success considerably depends on the willingness of developers to adopt the agile methodology. In this paper, we present a framework with drivers and inhibitors to the developer acceptance of Scrum. It combines analytical with empirical findings and can be used as a theoretical basis to empirically evaluate the actual support of Scrum in concrete scenarios. The introduced framework is based on the extended Technology Acceptance Model (TAM), which has been proven to be also applicable to describe the intention of developers to use a methodology. Building upon results from qualitative in-depth interviews with six experienced Scrum experts of a German DAX-30 company, we refine the general determinants of adoption contained in the TAM with several observed factors that influence the willingness of developers to use Scrum in practice

Do open access articles in economics have a citation advantage?

We investigate whether articles in economics that are freely available on the web have a citation advantage over articles with a gated access. Our sample consists of articles from 2005 from 13 economic journals (including the top five journals). In addition to standard mean comparisons we also use a negative-binomial regression model with several covariates to control for potential selection effects and quality bias. Using citation data from three different databases (Web of Science, RePEc and Google Scholar) we show that articles that are freely available on the internet have indeed a significantly higher citation count

Do open access articles in economics have a citation advantage?

We investigate whether articles in economics that are freely available on the web have a citation advantage over articles with a gated access. Our sample consists of articles from 2005 from 13 economic journals (including the top five journals). In addition to standard mean comparisons we also use a negative-binomial regression model with several covariates to control for potential selection effects and quality bias. Using citation data from three different databases (Web of Science, RePEc and Google Scholar) we show that articles that are freely available on the internet have indeed a significantly higher citation count