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Adaptive Moment Estimation (Adam) is a very popular training algorithm for deep neural networks, implemented in many machine learning frameworks. To the best of the authors knowledge no complete convergence analysis exists for Adam. The contribution of this paper is a method for the local convergence analysis in batch mode for a deterministic fixed training set, which gives necessary conditions for the hyperparameters of the Adam algorithm. Due to the local nature of the arguments the objective function can be non-convex but must be at least twice continuously differentiable.
One of the most popular training algorithms for deep neural networks is the Adaptive Moment Estimation (Adam) introduced by Kingma and Ba. Despite its success in many applications there is no satisfactory convergence analysis: only local convergence can be shown for batch mode under some restrictions on the hyperparameters, counterexamples exist for incremental mode. Recent results show that for simple quadratic objective functions limit cycles of period 2 exist in batch mode, but only for atypical hyperparameters, and only for the algorithm without bias correction. We extend the convergence analysis to all choices of the hyperparameters for quadratic functions. This finally answers the question of convergence for Adam in batch mode to the negative. We analyze the stability of these limit cycles and relate our analysis to other results where approximate convergence was shown, but under the additional assumption of bounded gradients which does not apply to quadratic functions. The investigation heavily relies on the use of computer algebra due to the complexity of the equations.
High labor cost in western countries allows cost savings by companies engaging in IS offshoring. However, studies worldwide indicate that a large number of companies that engaged in IS offshoring are not satisfied with the outcome. Our study examined the determinants of IS offshore project success: We developed a model and empirically tested it with data collected from 304 experts who reported on projects offshored from Germany to a wide range of near and distant countries. The model posited a direct effect of offshoring expertise and trust in offshore service provider (OSP) on success, as well as an indirect effect mediated by project suitability, knowledge transfer, and liaison quality. An analysis using partial least squares (PLSs) provided significant support for almost all these relationships. However, it showed that offshoring expertise played a minor role in explaining success and the mediating constructs. Trust in OSP had a small direct effect on success and a medium to large effect on the mediating constructs. Project suitability, knowledge transfer, and liaison quality all had small direct effects on success.
In der Produktion gilt „Lean Management“ als einer der de-facto Standardmanagementansätze. Lean Management in IT-Organisationen (Lean IT) ist dahingegen in der Praxis weniger verbreitet und in der Wissenschaft kaum erforscht. Dieser Beitrag aggregiert und erweitert die Ergebnisse mehrerer Forschungsarbeiten. Dabei werden vorrangig zwei Aspekte diskutiert: (1) Ein mögliches Einführungsmodell für Lean IT. Dieses verknüpft fünf Rollen (Sponsor, Programmleiter, Navigator, Linienführungskraft und Linienexperte) mit vier Phasen (Vorbereitung, Analyse, Gestaltung und Implementierung). (2) Besondere Herausforderungen für Linienführungskräfte, die aufgrund der „bottom up“-Ausrichtung bei Lean-IT-Einführungen stark gefordert werden. Neben einer klaren Vision für die Organisationseinheit und dem Verständnis, an welcher Stelle Lean IT die Organisationseinheit konkret unterstützen kann, benötigen sie Offenheit, Veränderungswillen und die Bereitschaft Verantwortung an Mitarbeiter zu delegieren. Außerdem sollten sie über ein ausreichendes Zeitbudget für die Einführung verfügen, um ihrer gestaltenden und qualitätssichernden Funktion nachkommen zu können.
Basierend auf einer systematischen und umfangreichen Analyse von Praxisbeiträgen zum Thema Schatten-IT, die zwischen September 2015 und August 2016 erschienen sind, beschreibt der vorliegende Artikel Governance-Aspekte zu diesem Phänomen. Er ergänzt damit vorhergehende akademische Studien. Es zeigt sich, dass unter Praktikern der Eindruck vorherrscht, dass IT-Abteilungen unter zunehmendem Druck stehen, schneller auf sich ändernde Anforderungen aus den Fachbereichen reagieren zu müssen. Können IT-Abteilungen diesen Erwartungen nicht entsprechen, beschaffen sich Fachbereiche und Nutzer selbst Lösungen in Form von Schatten-IT. Als mögliche Antwort darauf kann sich die IT-Abteilung agiler organisieren und die IT-Architektur im Unternehmen modernisieren. Eine weitere Möglichkeit besteht darin, sich das innovative Potenzial von Schatten-IT zunutze zu machen und deren Umsetzung aktiv durch organisatorische und technische Maßnahmen zu unterstützen. IT-Sicherheitsmanagement und technische Schutzmechanismen können helfen, die so entstandenen Lösungen abzusichern und die Risiken zu minimieren. Nach vorherrschender Ansicht entwickelt sich die IT-Abteilung als Konsequenz aus all diesen Maßnahmen zu einem nutzerorientierten, internen Service-Provider und strategischen Partner für die Fachbereiche.
An increasing amount of IS offshoring research has been published during the last four years. This paper presents a comprehensive view of the field of study from a managerial point of view. It provides a consolidated view of the field of study between 2010 and 2013 based on a manual search comprising 69 selected journals and 9 conferences, as well as a search using 6 journal databases. The literature review ensures continuity of research by connecting to a comprehensive literature analysis covering the years 1999 to 2009. This way it consolidates and critically reflects the state of the research of the last 14 years. Overall, we compiled 95 relevant publications originating from leading IS journals and IS conference proceedings. The results indicate that IS offshoring research is largely non-theory based, using almost entirely empirical data and interpretive research methods and -to a smaller extent -positivist research designs. The ISO research of the last 14 years focuses on the implementation stages "how" and "outcome" while the pre-implementation-stages “why”, “what”, and “which” are comparatively sparsely researched. Future studies should apply a more theory-driven approach with a greater attention on pre-implementation aspects of information systems offshoring. In addition, future research should investigate the special nature of near- and onshoring, captive offshoring as well asagile (project) management techniques suitable for ISO.
Lean Management is a standard production mode that has been familiar to production organizations for several decades. To date, however, academic literature has presented surprisingly little information about the application of Lean Management in Information Technology (IT) organizations, or what is called Lean IT. Drawing upon an empirical qualitative case study of the IT departments of two multinational companies, in this paper we identify change management lessons learned for Lean IT implementations, as well as seven characteristics of a corresponding change management approach. As an extension of our work, researchers should validate and expand our initial findings, preferably in a quantitative setting.
Information systems backsourcing describes the transferof previously outsourced activities, assets, or personnel back to the originating companyto regain ownership and control. While there is much research on information systems outsourcing, the topic of backsourcing information systemsis still an emerging research area. Therefore, ourpaper aims to explore and synthesizethe existing literature on information systemsbacksourcing, since there is no exhaustiveliteraturereview of the state of the research to our knowledge available yet. In this paper, wecreate a framework to structure the existing research along the overallbacksourcing process. We identifydifferent motivators, such asexpectation gaps, orinternal and external organizational changes, leading towards a backsourcing decision, and factors positively or negatively influencing this decision. Additionally, we derive implementation success factors based on the existing literature to guide companies through the backsourcing process.We also differentiate the term backsourcing from related, sometimes synonymously used terms, by emphasizing the change of ownership back to the company of originas the main criterion.Additionally, we discuss opportunities for future research in the field of information systems backsourcing.
Lean management (LM) is well established in manufacturing organizations, and LM adoption in service organizations has recently increased. However, we lack research that focuses on the success of lean management implementations in IT organizations (lean IT). This paper contributes to knowledge of the success factors of lean IT implementation and the relative importance of each factor based on the insights of field experts. The experts identified, agreed on, and ranked 12 implementation success factors for lean IT in a Delphi study using the best/worst scaling technique. The most important factors were leadership involvement, change culture and work ethic, employee involvement, and performance management. Factors of intermediate importance were implementation facilitation, training and education, clear vision and direction, long-term focus, communication, and a holistic approach. Least important factors were existing skills, organizational changes/standardization, and financial resources. This paper contributes a more nuanced understanding of the relative importance of lean IT success factors, proposes relationships between them, and comprehensively explains how to use the rigorous best/worst scaling method in a traditional ranking-type Delphi study.
It is state of technology in district heating systems to use sand as backfill material for district heating pipes (DHP). In conventional pipeline construction, Temporarily Flowable Backfill Materials (TFB) have been already used for backfilling the pipe zone. TFB consists of the excavated material, cement, water and optionally bentonite. Environmental and economic advantages are that the excavated material can be reused and that TFB requires no compaction. In order to embed district heating pipes in TFB, soil mechanical parameters of the TFB are required. Above all the resistance to temperature-induced axial displacement should be well-known in order to estimate the displacements of the DHP, as well as the stress distribution along the DHP. Compared to sand as a non-cohesive backfill TFB have remarkable adhesive contact stresses which result in considerable resistance forces.In this article, the contact behavior between TFB and DHP is described as well as the effect on the DHP statics. Therefore, the results of various laboratory tests are summarized and presented to understand the interface-resistance-characteristics (IRC) of the DHP/ TFB interface. Then, the deduced IRC was implemented in a computer program for some comparative calculations with sand and TFB. Finally, the results of cyclic loading are presented and discussed.