Ambient Service Research Articles

Study of Aging Characteristics for Metalized HTPB Based Composite Solid Propellants Stored in Ambient Conditions

The aging of any propellant is defined as the change in the physical, chemical, and performance parameters of solid rocket propellants. The propellant’s service life and aging properties are important parameters of the study, especially for missiles and other defense applications. Hydroxyl-terminated polybutadiene (HTPB) based composite solid propellants with ammonium perchlorate (AP) are the most prominently used propellants in the operations of solid rocket motors in the defense and space sectors. Thus, studying this composite solid propellant is of essential when determining ambient service life. Performance parameters studied in this research are burn rate under high-pressure conditions in Crawford bomb setup, Thermogravimetric Analysis, and Fourier Transform Infrared Spectroscopy (FTIR). SEM and X-ray diffraction (XRD) analysis of the aged sample were also conducted to ascertain the chemical composition and morphological changes in the samples. Naturally aged propellant strands manufactured in different years have been compared with freshly prepared ones to establish a trend for deriving conclusions. The results from different analysis techniques, FTIR, XRD, and FESEM, depicted that oxidation of metals happens while aging of propellant due to atmospheric moisture, and the metal oxides prominently affect the propellant chemical composition and decomposition process of the propellant samples. The ballistic properties of the aluminium added samples showed an increment in burn rate. In contrast, the bimetal addition of aluminium and magnesium combined as an additive decreased the ballistic burn rate.

Experimental method for creep characterization of polymeric foam materials in media immersion

Polymeric flexible foam materials are widely used as damping materials in structural applications primarily to reduce unwanted system vibrations and related noise generation. Due to the viscoelastic nature of polymers and high compressibility of soft polymeric foams, their damping quality is strongly dependent on the overall loading situation, which occasionally means complex mechanical loading scenarios combined with specific ambient service conditions. In the case of superimposed constant compressive loading the deformation of the damping components is basically dependent on the fundamental creep tendency of certain material type and is also strongly influenced by service temperature and the surrounding contact media. Thus the chosen test methodology for proper creep characterization has to reflect these major influencing parameters.In this regard, a specific creep testing device was built up for the performance of small load compression creep experiments on soft foam specimens immersed in liquid media, which was mineral oil in the present study. Moreover, the thermo-mechanical behavior of the foam materials was investigated by dynamic-mechanical analysis (DMA). The resulting temperature-dependent modulus and damping characteristics showed a good correlation with the corresponding creep behavior, enabling a rough estimation of the creep tendency within corresponding temperature ranges.

Peer to peer communication framework for 5G networks using Ambient Service

Efficient data routing in 5G radio access networks is still a challenging issue in present days. Therefore, Peer to Peer Communication Framework along with Ambient Service implementation for 5G networks is proposed to support Radio Access Network (RAN). RAN management energetically monitors network traffic for various backhaul networks. In addition, for supporting different Quality of Service (QoS) desires a corresponding scheme named Incorporated System Resource Administration (ISRA) is proposed and splits the resource requests in to various kinds of network slices. ISRA method selects the mini-cloud on basis of route resource requirement for direct peer to peer communication. Peer Dock functionality is applied over all existing peers in the network that has high-quality processing capacity accessible. Data is commonly stored at abode mini-cloud and freely moves from peer to peer and be backed up using peer dock process along with ambient service. Network slicing is the prominent method that offers network flexibility with cost efficient manner. This method greatly reduces bandwidth necessitate for backhaul networks. Simulation analysis is carried out and the results are compared with the conventional schemes.

Design Aspects of Positional Mooring System Based on LR FOIFL Rules

Floating offshore units, such as FPSOs, are subject to dynamic excitations from the environment and require to be moored to maintain position at the fix location of operation. In designing positional mooring systems for floating offshore units, systematic analyses must be performed to predict tension levels in the mooring lines and offsets of the floating unit under extreme and ambient service conditions, in order to ensure the mooring arrangement provides a level of safety acceptable to the industry. In order to derive environmental loads pertinent to the location of operation, environmental data should be made available comprising of long and short term current, wind and wave characteristic data specific to the site of operation. Based on LR FOIFL Rules, the performance of positional mooring systems is assessed on the basis of sets of site specific extreme and ambient (or fatigue) environmental conditions. Class rules require consideration of extreme conditions with recurrence period of 100 years (e.g. combination of 100 year waves + 100 year wind + 10 year current).In the process of designing positional mooring systems of FPSOs, designers may start from quasi-static analysis at preliminary design stage, and then investigate various combinations of extreme conditions in the dynamic analysis for a more rigorous approach during the final design stage.The outcomes of the analyses have to be compared against industry standards such as the LR FOIFL rules to confirm the positional mooring system’s design meets levels of safety recognised as acceptable to the industry. In this paper, an introduction to positional mooring systems for FPSOs, considering typical strength aspects is given, followed by a general description of hydrodynamic characteristics of ship shape FPSOs The design aspects of mooring system is then given in section outlining methodology in mooring analysis using either quasi-static or dynamic method.

Research and application of ambient air quality monitoring service based on data fusion

Requirement of air quality has become higher with the living standard development and population increase. Therefore, establish the efficient ambient air data detection and fusion service system based on wireless sensor network and device cloud will be more convenient for searching existent problems that can figure them out with benefit living and leave away from the damage of air pollution. Moreover, in order to improve the accuracy and reliability of multi-source heterogeneous data in collection process according to the analysis of the limitations and the features of data collected, a proper data fusion approach based on extended Dempster-Shafer theory is proposed to expose the faulty information of sensor nodes for monitoring service. Results validate that the service can effectively improve the ability in terms of flexibility and extensibility, decrease the inherent uncertainty of the signal detection and reduce the decision-making risk.

Research and application of ambient air quality monitoring service based on data fusion

Research and application of ambient air quality monitoring service based on data fusion

Identifying ambient service location problems and its application using a humanized computing model

The purpose of this study is to identify a humanized computing model for solving ambient service location problems with a developed heuristic algorithm. In real situations, space constraints may result in a practical facility location planning problem in an urban environment. Because of space constraints, large warehouse facilities may not be allocated for a single location; and they need to be partitioned and placed at different locations with synergy and collaboration patterns to fulfill orders for many retail facilities. Therefore, properly locating different types of warehouse facilities to make logistics and supply efficient is important. This study considers the multiple-distinct facilities service location problems (MDFSLP) that are constrained in four attributes of single sourcing, p-median, p-dispersion, and hierarchical location. Although past research has discussed the same types of warehouse location problems, the MDFSLP has sparsely been explored and reviewed. Thus, this study proposes a fast-iterated local search (FSILS) algorithm to solve the problem efficiently. The results show that the FSILS algorithm contributes to the better efficiency of computational time than other listed similar approaches and are of high importance in a realistic location environment to promote industry development on business strategies.

Knowledge-enabled decision making for robotic system utilizing ambient service components

Robotic and ambient intelligent environments are much more demanding regarding the knowledge a robot needs to have. A skilled robot performs human-scale manipulation tasks, interacts with a variety of objects, understands instructions given by humans and most importantly, requires the capability of interpreting ubiquitous resources and assembling them into a complex plan. In this paper, a novel Knowledge-enable Decision Making Framework KDMF is proposed for Component-Based Robotic System CBRS. We exploit that the use of domain knowledge is pivotal to endow robots with higher degrees of autonomy and intelligence in CBRS. Ontology knowledge about classes, properties, relations is organized in OWL based conceptual map, which allows automated inference to derive new pieces of information. Knowledge about tasks is specified in a tree data structure, and knowledge about components' functions is formulated by a specific type of service specification profile. Using the knowledge representation, a task-oriented decision making method is proposed that integrates knowledge inference and service components utilization. In practical applications of ambient and robotic assisted living, robot's plans generated by the decision making software are based on the knowledge of components, rather than particular device instances, which improves the reusability and flexibility of the system. Experimental results validate the effectiveness of the proposed method.

Unified trust establishment by leveraging remote attestation – modeling and analysis

Purpose – Ambient service provisioning with the least human participation in a pervasive computing environment, which is composed of interconnected devices and sensors, raises several trust and security issues. Accurate measuring of the integrity of the nodes that are willing to interact in this intimate environment can boost the trust evolution process, particularly in the uncertainty state and initiation phase. The paper aims to discuss these issues. Design/methodology/approach – The paper presents a unified approach in calculating the trust value among the nodes by leveraging some trusted computing functionalities. The approach aggregates different trust metrics like context, recommendation, and history to compute the trust index of each party more accurately. The paper also describes several existing remote attestation techniques including the chosen attestation technique for the model. The paper simulated the behaviour of the model in different scenarios and evaluates its responsiveness when the trustworthiness among peer nodes can be attested. Findings – The results obtained from different simulated scenarios demonstrate the usefulness of the proposed model. It is shown that trust evaluation process in the proposed model is very granular and also can be fine-tuned according to the application and context. The model strength in solving the uncertain situations and assigning appropriate initial trust values is shown, as well. Finally, the paper describes the future research plan to evaluate the accuracy of the model. Originality/value – The novel idea of applying remote attestation in trust determination may open up new avenues of research in the study of trust management and trust models.

Influence of modifying methods on quality of eutectic and hypereutectic silumine for diesel engine pistons

The results of the investigation of the influence of different modifiers (sodium, phosphorus, antimony and strontium) on the quality of AlSi12CuMgNi and AlSi18CuMgNi alloys, which are used for the production of pistons, are presented in this paper. The effects of these elements were investigated with reference to their mechanical and structural properties measured at ambient and elevated temperatures and service performance of the piston. Since strontium and antimony modified alloys are not considered as standardised piston alloys, the research results were compared with the results of standard phosphor and sodium modified alloys normally used at globally renowned piston manufacturer: Mahle, KS.

An Efficient Ambient Service Model based on Personalizing Real-Life Space, and the Implementation of a Game Application

An Efficient Ambient Service Model based on Personalizing Real-Life Space, and the Implementation of a Game Application

Semantic Handover among Distributed Coverage Zones for an Ambient Continuous Service Session

In a user-centric approach, the end-user wants the best Quality of Experience (QoE) and the highest context-awareness. Throughout end-user’s spatial mobility, service providers must continuously adapt the end-user’s service session according to his or her new ambient context, without neglecting functional preferences and demanded Quality of Service (QoS). Many spatial mobility management solutions have been conceived to help operators managing the network part of their end-users’ sessions. However, this problem is not yet investigated on the service layer. For this purpose, the authors propose in this paper the concept of semantic handover. This concept acts on the service layer by analogy to the network’s handover mechanisms. It is based on three complementary roles: the initiator, that detects a spatial mobility and initiates the semantic handover; the decider, that decides which services should be replaced in the end-user’s service session and what are their ubiquitous ambient counterparts; and the executor, that executes the decision and adapts the end-user’s service session to the new ambient context. This solution is based on highly scalable distributed coverage zones. Service providers must deploy their ubiquitous services, having the same functionality and an equivalent QoS, in different geographic areas, and they must associate each service to a specific coverage zone. Therefore, when the end-user moves among coverage zones, a semantic handover is launched to guarantee seamless service continuity throughout end-user’s ambient contexts.

Providing relevant information in an ambient services using service requester’s “logical area”

Ambient service is a kind of context-aware services which is related to the surrounding environment of the users. In other words, geographic area around the users is considered as contextual data to provide services. This geographical area around the user is called logical area which would be equivalent for “here” from an ordinary user’s point of view. Most of the time users are looking for resources around themselves or “here”. When “here” area of a user is overlapped or contained by a service area; which called “service domain” in ambient services; then user can get the service. So it is very important to know where is “here”. “Here” is a fuzzy spatial concept which is being frequently used in daily speaking. So it may be stated in requests of users e.g., finding cheapest restaurant “here” or around of somebody. The main step in a spatial context-aware application is determination of relevant information. Hence “here” concept, as a fundamental spatial concept, helps to provide relevant information to users so features located “here” or around of users, in which the best answer is located, should be found. As result, the area of “here” is very important to provide service in such cases. This issue becomes more complicated and important if the service requester is a mobile user, because the area of “here” changes over the time. In that case additional concepts and computations are needed to find “here” of that user. This paper is focused on modeling of “here” in an ambient service framework based on fuzzy set theory.

A human-centric framework for context-aware flowable services in cloud computing environments

Services are expected to be a promising way for people to use information and computing resources in our emerging ubiquitous network society and cloud computing environments. In this study, we propose a metaphoric concept called a flowable service. It is defined as a logical stream that organizes and provides circumjacent services in such a way that they are perceived by individuals to be naturally embedded in their surrounding environments. We present our view on how some of these problems, such as the flexibility, portability and interoperability of services, can be solved using flowable services in order to provide a seamless integration of diverse services in the most intuitive “flowable” way possible, thus achieving maximum satisfaction for both service providers and consumers while decreasing the delivery cost of the services. Recognizing the importance of the awareness of each individual’s context for a smooth and accurate provision of services, we further propose a human-centric framework for context-aware flowable services, which harnesses the users’ contexts to enable a pro-active support of human activities in a flexible and natural way. Owing to context-awareness, this framework can find and integrate circumjacent services that are considered needed by each individual and can create an ambient service environment that is tailored to his/her specific needs, proclivities and characteristics.

Ambient shopping advertisement using rough service domain

Ambient service is a kind of context aware services which is related to the surrounding environment of the users. In other word, geographic area around the users is considered as contextual data to provide services. So ambient services term is used to emphasize the association of context aware services with geographic areas called ambient service domain. Service domains have sharp and clear boundaries in current ambient services. However because of inaccurate positioning systems and some linguistic and fuzzy phrases used to define ambient service domain (e.g. around, here, far, near), it is necessary to define service domains in a framework which can handle their uncertainty. If an uncertain spatial object is modeled in a certain and crisp framework, some of data related to that object will be missed. In this regard, rough set theory, as a simple and powerful device to consider uncertainty, is considered to model ambient service domains and based on them, ambient services are provided to users. To test our model, users commented on ambient shop based on rough service domain and compare it with classic ambient shop, 73% of users became more interested in rough based version because some of users in classic services were excluded and did not receive services whereas they are getting services in rough based version.

Flexible ambient service discovery and composition for component-based robotic system

Combing ambient intelligence with service robots has shown great potentials in generating radically new system architecture, namely Component-Based Robotic System CBRS. In order to enable robot to automatically and flexibly utilize service resources in intelligent environment, a novel semantic-quantitative hierarchical service composition method is proposed for supporting complex task accomplishment. A service model with two-layered structure is put forward which incorporates ontology-based service functionality abstraction and state information of individual service resources. A set of unified semantic matching rules are established, based on which a bidirectional breadth-first traversal search algorithm inspired by the maze problem is proposed, which is capable of reliably and dynamically generating plans according to the task requirement. Applications in domestic service robot scenarios are described and experimental results validate the effectiveness of the proposed method.

Self-organized service placement in ambient intelligence environments

Ambient Intelligence (AmI) is an IT concept by which mobile users shall be seamlessly supported in their everyday activities. This includes interactions with remote resources as well as with their current physical environment. We have developed the so-called Ad hoc Service Grid (ASG) infrastructure that supports the latter form of interactions. It allows operators to cover arbitrary locations with ambient services in a drop-and-deploy fashion. An ambient service may autonomously distribute (replicate and migrate) within an ASG network to optimize its availability, response times, and network usage. In this article, we propose a fully decentralized, dynamic, and adaptive service placement algorithm for AmI environments like the ASG. This algorithm achieves a coordinated global placement pattern that minimizes the communication costs without any central controller. It does not even require additional communication among the replicas. Moreover, placement patterns stabilize if no changes occur in the environment while replicas still retain their ability to adapt. Mechanisms for self-organized placement of services are very important for AmI environments in general since they allow for autonomous adaptations to dynamic changes and, thus, remove the need for manual (re)configuration of a running system. We present a detailed evaluation of the algorithm's performance and compare it with three other algorithms to show its competitiveness. Furthermore, we discuss how the desired self-organizing behavior emerges from the interactions of a few simple, local rules that govern the individual placement decisions. In order to do so, we give an in-depth analysis of a series of emergent effects that are not directly encoded into the placement algorithm but stem from its collective dynamics.

Designing a usable ambient intelligence system

The design of the ambient intelligence service interface should be seen as an evolutionary object that continually changes to adapt to the emerging needs of the users. Context-awareness is a key feature of ambient computing. There is currently very little research conducted on how we can support the design of usable context-aware homes through ambient intelligence. Although principles of traditional interface design can be useful, we need to go beyond usability by looking at design parameters that deal with the contextual issues of these systems. Activity theory incorporates the notions of intentionality, history, mediation, motivation, understanding, culture and community into design. In particular, it provides a framework in which the critical issue of context can be taken into account. This paper studies how activity theory can be used for analysing user needs in order to design an ambient intelligence home.

Thermal degradation of acrylonitrile–butadiene–styrene (ABS) blends

This work investigates the accelerated thermal degradation of acrylonitrile–butadiene–styrene (ABS) due to aging at elevated temperatures (>80 °C). The impact resistance is shown to decrease dramatically beyond a critical aging time at 120 °C and this reduction strongly depends on surface property modifications during aging. Visual examination of specimen cross-sections after aging, verifies that (dis)colouration is limited to a surface layer, which is characteristic of degradation where oxygen diffusion into the bulk is limited. Degradation is supported by chemiluminescence assessment, which shows a rapid depletion of residual stabiliser within this layer as compared to the bulk polymer. Micro-indentation measurements also indicate that degradation causes an increase in Young's modulus at the specimen surface, which in turn promotes brittle failure. It is proposed that a critical depth of degradation (approximately 0.08 mm) forms on the surface of ABS due to aging. Applied loading initiates microcracks in this degraded layer, which propagate rapidly, causing bulk failure. Absorbance bands from Fourier transform infra-red spectroscopy indicate that surface degradation proceeds by chain scission and cross-linking in the polybutadiene (PB) phase of aged ABS specimens. Cross-linking is also supported by positron annihilation lifetime spectroscopy, which shows a decrease in free volume sites at the surface of aged specimens. Dynamic mechanical thermal analysis also supports the occurrence of cross-linking, as shown by an increase in the glass transition temperature of the PB phase after aging. Although degradation in the styrene–acrylonitrile (SAN) phase is less significant to the reduction in overall mechanical properties of ABS compared to the PB phase, an assessment of SAN copolymer indicates that heat aging decreases impact resistance. The contribution of SAN to the overall mechanical properties of ABS is also reflected by aging ABS specimens at temperatures just below the glass transition of the SAN phase (∼112 °C). The mechanism of thermal degradation is shown to be non-Arrhenius and governed by diffusion-limited oxidation. The long-term impact strength of ABS at ambient temperature is extrapolated from short-term data at elevated temperatures. As temperature and aging time influence degradation, it is proposed that at ambient service temperatures (40 °C), the degradation mechanism differs to that at elevated temperatures, and comprises both surface and bulk polymer degradation effects.

The Effect of Superplastic Deformation on Subsequent Service Properties of Fine Grained 7475 Al

Intergranular cavitation may be a limiting factor in the otherwise highly promising commercial exploitation of the recently developed superplastic forming process for the high strength aluminum alloy, 7475. A preliminary investigation has been carried out to quantify the effects of superplastic deformation on the major ambient temperature service properties. It is shown that the properties most degraded by the development of cavitation after large superplastic strains are those that depend on the local strain at tensile fracture. This affects, mainly, ductility and fatigue life. However, the effects are not generally significant below effective superplastic strains of about 0.8 to 0.9 (120–150 percent elongation) with the optimum forming conditions (T=516°C, ε˙=2×10−4 s−1). Furthermore, since the fine grain processing has an initial beneficial effect on the ductility-related properties, compared to conventionally processed sheet, most superplastically formed components would suffer very litle, if any, design penalties.