Not all GKK τ\tau-matrices are stable

Hermitian positive definite, totally positive, and nonsingular M-matrices enjoy many common properties, in particular: (A) positivity of all principal minors, (B) weak sign symmetry, (C) eigenvalue monotonicity, (D) positive stability. The class of GKK matrices is defined by properties (A) and (B), whereas the class of nonsingular $\tau$-matrices by (A) and (C). It was conjectured that: (A), (B) implies (D) [D. Carlson, J. Res. Nat. Bur. Standards Sect. B 78 (1974) 1-2], (A), (C) implies (D) [G.M. Engel and H. Schneider, Linear and Multilinear Algebra 4 (1976) 155-176], (A), (B) implies a property stronger than (D) [R. Varga, Numerical Methods in Linear Algebra, 1978, pp. 5-15], (A), (B), (C) implies (D) [D. Hershkowitz, Linear Algebra Appl. 171 (1992) 161-186]. We describe a class of unstable GKK $\tau$-matrices, thus disproving all four conjectures.Comment: 7 page

AI-based Conversational Agents for Customer Service – A Study of Customer Service Representative’ Perceptions Using TAM 2

This study aimed to identify the various factors that may influence customer service representatives’ perceptions of artificial intelligence (AI)-based conversational agents (CAs) for customer service. By analyzing 180 publications, a conceptual research model is developed for identifying the factors that may influence customer service representatives’ perceptions of AI-based CAs for customer service. The underlying conceptual research model comprises ten factors. The study is grounded in the application of the Technology Acceptance Model 2 (TAM 2) approach. The research model is empirically evaluated with survey data from 128 participants. Our results show that the direct positive effect of subjective norm on customer service representatives’ perception of using AIbased CAs in customer service decreases with increasing experience. Moreover, our results reveal new insights regarding trust. The results of this study provide an overview of the predominant characteristics of the influencing factors of customer service representatives’ perceptions of AI-based CAs for customer service

Effects, but no interactions, of ubiquitous pesticide and parasite stressors on honey bee (Apis mellifera) lifespan and behaviour in a colony environment

Interactions between pesticides and parasites are believed to be responsible for increased mortality of honey bee (Apis mellifera) colonies in the northern hemisphere. Previous efforts have employed experimental approaches using small groups under laboratory conditions to investigate influence of these stressors on honey bee physiology and behaviour, although both the colony level and field conditions play a key role for eusocial honey bees. Here, we challenged honey bee workers under in vivo colony conditions with sublethal doses of the neonicotinoid thiacloprid, the miticide tau-fluvalinate and the endoparasite Nosema ceranae, to investigate potential effects on longevity and behaviour using observation hives. In contrast to previous laboratory studies, our results do not suggest interactions among stressors, but rather lone effects of pesticides and the parasite on mortality and behaviour, respectively. These effects appear to be weak due to different outcomes at the two study sites, thereby suggesting that the role of thiacloprid, tau-fluvalinate and N. ceranae and interactions among them may have been overemphasized. In the future, investigations into the effects of honey bee stressors should prioritize the use of colonies maintained under a variety of environmental conditions in order to obtain more biologically relevant data

Adoption of Fourth Party Logistics in the Sector of German Agricultural Bulk Logistics - A Technology-Organization-Environment Framework Approach

This article aims at developing an understanding of the factors that promote the adoption of fourth party logistics (4PL) within German agricultural bulk logistics; hereafter referred to as diffusion factors. In order to elaborate upon the diffusion factors, we based our research on an exploratory study, and applied the Technology-Organization-Environment (TOE) framework. Within the scope of our research, we extracted those factors (e.g. external and internal logistics information technology, technology, size, services) predominantly contributing to the adoption of a 4PL approach. The study concentrates on the sector of German agricultural bulk logistics in which the 4PL approach is not implemented yet. The findings have important implications for the development of a 4PL approach within the sector. Our study provides an overview of prevailing characteristics of further diffusion factors in view of the main technologies, organizational structures and environmental influences

Status quo und Entwicklungsperspektiven des Fourth Party Logistics Provider (4PL)-Ansatzes – Eine Mixed-Methods-Untersuchung

Die vorliegende Arbeit zur Logistik,verstanden als eine anwendungsorientierte Wissenschaftsdisziplin, verfolgt eine wissenschaftliche sowie praxisorientierte Zielsetzung. Als übergeordnetes Ziel ist die Feststellung des Status quo und der Entwicklungsperspektiven des 4PL-Ansatzes anzuführen. Durch die Verwendung von etablierten Forschungsmethoden wird die wissenschaftliche Rigorosität sichergestellt. Zur Erfüllung der praxisorientierten Zielsetzung wurden Fallstudien und Experteninterviews im Rahmen des Forschungsprozesses verwendet, um zum einen das Wissen aus der Praxis einzubinden und zum anderen eine Relevanz für die Praxis sicherzustellen. Für eine konsistente Praxis-Orientierung wurde die Branche der landwirtschaftlichen Schüttgutlogistik als exemplarisches Anwendungsfeld zur Untersuchung des 4PL-Ansatzes gewählt. Die Schüttgutlogistik beschreibt das Bindeglied zwischen der Landwirtschaft, dem Handel und der Ernährungsindustrie und somit einen Teil eines Netzwerkes. Das Transportvolumen betrug im Jahr 2010 ca. 3,5 Mrd. t, wobei 76 % (2,7 Mrd. t) auf den Straßenverkehr entfielen (Bundesministerium für Ernährung, Landwirtschaft und Verbraucherschutz 2010). In Anlehnung an die Trends der Logistik konnten gefestigte und klassische Strukturen vorgefunden werden, weshalb der 4PL-Ansatz als wahre Innovation untersucht werden konnte. Dies ist dadurch begründet, dass die Branche über genossenschaftliche Strukturen verfügt und neue technologische Trends eher zurückhaltend verfolgt. Dennoch sind die logistischen Herausforderungen wie die Reduzierung von Leerkilometern, die Optimierung der Frachtraumkapazitäten sowie die CO2-Reduzierung laut den befragten Akteuren der Branche von hoher Bedeutung (Müller 2010). Im Rahmen dieser Arbeit wurden daher Methoden, Modelle, Applikationen und Vorgehensweisen entwickelt, welche zur Beantwortung der folgenden übergeordneten Forschungsfragen herangezogen werden: 1. Was ist der Status quo des 4PL-Ansatzes sowie das Anforderungsprofil der landwirtschaftlichen Schüttgutlogistik an den 4PL? 2. Was sind die wichtigsten Diffusionsfaktoren des 4PL-Ansatzes in der deutschen landwirtschaftlichen Schüttgutlogistik? 3. Was sind die Potenziale innerhalb einer Branche durch Einführung eines 4PL? 4. Wie können eine Implementierung sowie die organisatorische Einordnung des 4PL-Ansatzes für eine Branche erfolgen? 5. Welche Trends der Zukunft zeigen Parallelen zum 4PL-Ansatz auf? Die vorliegende kumulative Dissertation zeigt Potenziale für die Branche auf und trägt zum Verständnis einer zukünftigen Entwicklung des 4PL-Ansatzes bei. Zur Zielerreichung wird ein Mixed-Methods-Ansatz verfolgt

A Fourth Party Logistics Provider within an Inter-Organizational Network: An explorative Study with the Example of the Agricultural Bulk Logistics Industry

This exploratory study provides an understanding of how the Fourth Party Logistics Provider (4PL) approach affects the development of inter-organizational networks within the agricultural sector. A research within the German agricultural bulk logistics industry discovered that the 4PL approach coincides with the ongoing technical development of the industry and enables them to provide crucial functions for these networks. Moreover, the functions of a 4PL may induce an efficiency-enhancing effect for a network. The greatest identified potentials are: (1) Information and communication technologies (ICT) support a more efficient transportation planning as well as more transparency, and enhance the degree of cooperation within the network and its inter-organizational dynamic; (2) If the 4PL approach adapts to inter-organizational forms of coordination, than new experiences for the development of 4PL (increased commitment, cooperation strategies) may be expected; (3) If the 4PL claims technological leadership within the industry, this result in a long-term competitive advantage