Programming with event loops and control loops – From actors to agents

Event loops are a main control architecture to implement actors. In this paper we first analyse the impact that this choice has on the design of actor-based concurrent programs. Then, we discuss control loops as the main architecture adopted to implement agents, and we frame them as an extension of event loops effective to improve the programming of autonomous components that need to integrate both reactive and proactive behaviors, in a modular way.     

Can smartphones be specialists? Effects of specialization in mobile advertising

Based on the Computers Are Social Actors (CASA) paradigm, this study extends the expectations regarding the superiority of specialists over generalists to mobile technology by examining whether the specialization of a hardware agent (i.e., a smartphone) and a software agent (i.e., an application) has psychological effects on smartphone users who are exposed to mobile advertisements. Results from a between-subjects experiment (N = 80) show that specialist smartphones and applications induce greater trust in advertisements and an increased purchase intention toward the advertised products than generalist smartphones and applications. In addition, the effects of specialization on purchase intention are mediated by trust in advertisements. Theoretical and practical implications of these findings are discussed.     

A model of domain-polymorph component for heterogeneous system design

Heterogeneous systems mix different technical domains such as signal processing, analog and digital electronics, software, telecommunication protocols, etc. Heterogeneous systems are composed of subsystems that are designed using different models of computation (MoC). These MoCs are the laws that govern the interactions of the components of a subsystem. The design of heterogeneous systems includes the design of each part of the system according to its specific MoC, and the connection of the parts in order to build the model representing the system. Indeed, this model allows the MoCs that govern different parts of system to coexist and interact.To be able to use a component which is specified according to a given MoC, under other, different MoCs, we can use either a hierarchical or a non-hierarchical approach, or we can build domain-specific components (DSC). However, these solutions present several disadvantages. This paper presents a new model of component, called domain-polymorph component (DPC). Such a component is atomic and is able to execute its core behavior, specified under a given MoC, under different host MoCs. This approach is not a competitor to the approaches above but is complementary.     

Development of virtual data acquisition systems based on multimedia internetworking

This paper proposes a novel approach centered on multimedia internetworking for the development of Distributed Virtual Instruments (DVI). Multimedia internetworking refers to network infrastructures, protocols, models, applications and techniques being currently deployed over the Internet to support multimedia applications, e.g., videoconferencing, video-on-demand, shared workspaces. It is applied to broaden the concept of virtual instrument and enable new measurement patterns leveraging efficiency and interactivity. A DVI is a virtual instrument split into possibly multiple and independent parts, sender and receiver, which are linked by real-time continuous media and control streams. Senders and receivers are built by using open, composable and modular components based on a time sensitive actor framework and glued by multimedia middleware. A prototype is described to demonstrate the potential and the benefits of the proposed approach.     

The Attenuated Secretion of Hyaluronan by UVA-Exposed Human Fibroblasts Is Associated with Up- and Downregulation of HYBID and HAS2 Expression via Activated and Inactivated Signaling of the p38/ATF2 and JAK2/STAT3 Cascades

Little is known about the effects on hyaluronan (HA) metabolism of UVA radiation. This study demonstrates that the secretion of HA by human dermal fibroblasts (HDFs) is downregulated by UVA, accompanied by the down- and upregulation of mRNA and protein levels of the HA-synthesizing enzyme (HAS2) and the HA-degrading protein, HYaluronan Binding protein Involved in HA Depolymerization(HYBID), respectively. Signaling analysis revealed that the exposure distinctly elicits activation of the p38/MSK1/CREB/c-Fos/AP-1 axis, the JNK/c-Jun axis, and the p38/ATF-2 axis, but downregulates the phosphorylation of NF-kB and JAK/STAT3. A signal inhibition study demonstrated that the inhibition of p38 significantly abrogates the UVA-accentuated mRNA level of HYBID. Furthermore, the inhibition of STAT3 significantly downregulates the level of HAS2 mRNA in non-UVA exposed HDFs. Analysis using siRNAs demonstrated that transfection of ATF-2 siRNA but not c-Fos siRNA abrogates the increased protein level of HYBID in UVA-exposed HDFs. An inhibitor of protein tyrosine phosphatase but not of protein serine/threonine phosphatase restored the diminished phosphorylation level of STAT3 at Tyr 705, accompanied by a significant abolishing effect on the decreased mRNA expression level of HAS2. Silencing with a protein tyrosine phosphatase PTP-Meg2 siRNA revealed that it abrogates the decreased phosphorylation of STAT3 at Tyr 705 in UVA-exposed HDFs. These findings suggest that the UVA-induced decrease in HA secretion by HDFs is attributable to the down- and upregulation of HAS2 and HYBID expression, respectively, changes that are mainly ascribed to the inactivated signaling of the STAT3 axis due to the activated tyrosine protein phosphatase PTP-Meg2 and the activated signaling of the p38/ATF2 axis, respectively.     

Potential for mycotoxin-producing fungal growth in various agro-ecological settings and maize storage systems in southwestern Ethiopia

The objective of this study was to evaluate the potential growth of mycotoxin-producing fungi under different agro-ecological settings and storage methods in southwestern Ethiopia. The districts of Sokoru, Omonada, and Dedo, representing three agro-ecological settings, were considered for the study. Six farmers' fields were selected from each agro-ecology for monitoring pre-harvest weather conditions, while three farmers' and three collectors' storage systems were considered for post-harvest study. Additional warehouses were also included for current study. Fungal pathogens were isolated and identified once per month over a six-month storage period. Both long-term climate and pre-harvest weather data indicated that all agro-ecological conditions were conducive to the growth of the target fungal species. Temperatures inside the farmers' storage systems showed significant (P = 0.04) positive correlations with ambient conditions. Significant (P < 0.05) positive correlations were also observed between the relative humidity under the farmers' storage and the ambient conditions. In contrast, there were no significant correlations between the collector's storage and ambient conditions for either temperature or relative humidity. A simple linear regression model revealed that there was a negative relationship between frequency of mycotoxin-producing fungi and the temperature inside the farmers' storage systems; whereas, fungal occurrence was positively and significantly (P < 0.05) correlated with the relative humidity. Both temperature and humidity were associated with fungal frequency of occurrence in the collectors' store-houses and the wholesalers' warehouses. The farmers' traditional storage methods are not climatically controlled to maintain post-harvest product quality. Therefore, a simple and accessible climate-controlled storage structure is necessary for the resource-poor growers of the study area.     

Smartphones as Social Actors? Social dispositional factors in assessing anthropomorphism

Smartphones are prominently personalized and personified in our society. Existing Computers as Social Actors (CASA) studies about anthropomorphism and social interactions have focused on how to identify and elicit positive anthropomorphic effects but have seldom addressed motivations and dispositional factors of the user. Through an online survey that incorporates validated social psychological scales, this study provides empirical evidence that smartphone users’ social disposition, including factors of chronic loneliness, attachment style, and cultural orientation, is associated with their acceptance and awareness of anthropomorphism. The findings corroborate and add to the theory of sociality determinant of anthropomorphism, the computing technology continuum of perspective, and the CASA paradigm.     

A modular approach to real-time programming using actors and Java

This paper describes an actor-based approach to real-time programming, which focuses on the separation of functional from timing behaviour. The approach favours modularity and time predictability. Clusters of actors, allocated on distinct processors, are orchestrated by a control machine which provides an event-driven and time-driven customisable scheduling framework. The approach can be hosted by Java, which fosters a clean and type-safe programming style. Temporal analysis can be formally assisted by Coloured Petri Nets.