Towards more flexible Architecture Description Languages for industrial applications

Architecture Description Languages (ADLs) have emerged in recent years as a tool for providing high-level descriptions of software systems in terms of their architectural elements and the relationships among them. Most of the current ADLs exhibit limitations which prevent their widespread use in industrial applications. In this paper, we discuss these limitations and introduce ALI, an ADL that has been developed to address such limitations. The ALI language provides a rich and flexible syntax for describing component interfaces, architectural patterns, and meta-information. Multiple graphical architectural views can then be derived from ALI's textual notation.

Relational architecture description language for software families

Software Product-Line Engineering has emerged in recent years, as an important strategy for maximising reuse within the context of a family of related products. In current approaches to software product-lines, there is general agreement that the definition of a reference-architecture for the product-line is an important step in the software engineering process. In this paper we introduce ADLARS, a new form of architecture Description language that places emphasis on the capture of architectural relationships. ADLARS is designed for use within a product-line engineering process. The language supports both the definition of architectural structure, and of important architectural relationships. In particular it supports capture of the relationships between product features, component and task architectures, interfaces and parameter requirements.

Analysis of Transonic Limit Cycle Oscillations under Uncertainty

For the computation of limit cycle oscillations (LCO) at transonic speeds, CFD is required to capture the nonlinear flow features present. The Harmonic Balance method provides an effective means for the computation of LCOs and this paper exploits its efficiency to investigate the impact of variability (both structural a nd aerodynamic) on the aeroelastic behaviour of a 2 dof aerofoil. A Harmonic Balance inviscid CFD solver is coupled with the structural equations and is validated against time marching analyses. Polynomial chaos expansions are employed for the stochastic investiga tion as a faster alternative to Monte Carlo analysis. Adaptive sampling is employed when discontinuities are present. Uncertainties in aerodynamic parameters are looked at first followed by the inclusion of structural variability. Results show the nonlinear effect of Mach number and it’s interaction with the structural parameters on supercritical LCOs. The bifurcation boundaries are well captured by the polynomial chaos.

'Conditional candour' and 'knowing me': an interpretive description study on patient preferences for physician behaviours during end-of-life communication

OBJECTIVE: To understand patients' preferences for physician behaviours during end-of-life communication.

METHODS: We used interpretive description methods to analyse data from semistructured, one-on-one interviews with patients admitted to general medical wards at three Canadian tertiary care hospitals. Study recruitment took place from October 2012 to August 2013. We used a purposive, maximum variation sampling approach to recruit hospitalised patients aged ≥55 years with a high risk of mortality within 6-12 months, and with different combinations of the following demographic variables: race (Caucasian vs non-Caucasian), gender and diagnosis (cancer vs non-cancer).

RESULTS: A total of 16 participants were recruited, most of whom (69%) were women and 70% had a non-cancer diagnosis. Two major concepts regarding helpful physician behaviour during end-of-life conversations emerged: (1) 'knowing me', which reflects the importance of acknowledging the influence of family roles and life history on values and priorities expressed during end-of-life communication, and (2) 'conditional candour', which describes a process of information exchange that includes an assessment of patients' readiness, being invited to the conversation, and sensitive delivery of information.

CONCLUSIONS: Our findings suggest that patients prefer a nuanced approach to truth telling when having end-of-life discussions with their physician. This may have important implications for clinical practice and end-of-life communication training initiatives.

Prediction of Limit Cycle Oscillations Using an Implicit Aeroelastic-Harmonic Balance Method

This work proposes a extends a novel approach to compute tran sonic Limit Cycle Oscillations using high fidelity analysis. CFD based Harmonic Balance methods have proven to be efficient tools to predict periodic phenomena. This paper’s contribution is to present a methodology to determine the unknown frequency of oscillations using an implicit for- mulation of the HB method to accurately capture Limit Cycle Oscillations (LCOs); this is achieved by defining a frequency updating procedure based on a coupled CFD/CSD Harmonic Balance formulation to find the LCO condition. A pitch/plunge aerofoil and respective linear structural models is used to exercise the new method. Results show consistent agreement between the proposed and time-marching methods for both LCO amplitude and frequency.

Investigation of Limit Cycle Oscillations Using Aeroelastic-Harmonic Balance Method

This work investigates limit cycle oscillations in the transonic regime. A novel approach to predict Limit Cycle Oscillations using high fidelity analysis is exploited to accelerate calculations. The method used is an Aeroeasltic Harmonic Balance approach, which has been proven to be efficient and able to predict periodic phenomena. The behaviour of limit cycle oscillations is analysed using uncertainty quantification tools based on polynomial chaos expansions. To improve the efficiency of the sampling process for the polynomial-chaos expansions an adaptive sampling procedure is used. These methods are exercised using two problems: a pitch/plunge aerofoil and a delta-wing. Results indicate that Mach n. variability is determinant to the amplitude of the LCO for the 2D test case, whereas for the wing case analysed here, variability in the Mach n. has an almost negligible influence in amplitude variation and the LCO frequency variability has an almost linear relation with Mach number. Further test cases are required to understand the generality of these results.

Prediction of limit cycle oscillations under uncertainty using a Harmonic Balance method

The Harmonic Balance method is an attractive solution for computing periodic responses and can be an alternative to time domain methods, at a reduced computational cost. The current paper investigates using a Harmonic Balance method for simulating limit cycle oscillations under uncertainty. The Harmonic Balance method is used in conjunction with a non-intrusive polynomial-chaos approach to propagate variability and is validated against Monte Carlo analysis. Results show the potential of the approach for a range of nonlinear dynamical systems, including a full wing configuration exhibiting supercritical and subcritical bifurcations, at a fraction of the cost of performing time domain simulations.

Microstructure evolution in CLAM steel under low cycle fatigue

In the process of room-temperature low cycle fatigue, the China Low Activation Martensitic steel exhibits at the beginning cyclic hardening and then continuous cyclic softening. The grain size decreased and the martensitic lath transformed to cells/subgrains after the tests. The subgrains increase in size with increasing strain amplitude.

Low cycle fatigue properties of CLAM steel at 823 K

China Low Activation Martensitic (CLAM) steel is considered to be the main candidate material for the first wall components of future fusion reactors in China. In this paper, the low cycle fatigue (LCF) behavior of CLAM steel is studied under fully reversed tension–compression loading at 823 K in air. Total strain amplitude was controlled from 0.14% to 1.8% with a constant strain rate of 2.4×10−3 s−1. The corresponding plastic strain amplitude ranged from 0.023% to 1.613%. The CLAM steel displayed continuous softening to failure at 823 K. The relationship between strain, stress and fatigue life was obtained using the parameters obtained from fatigue tests. The LCF properties of CLAM steel at 823 K followed Coffin–Manson relationship. Furthermore, irregular serration was observed on the stress–strain hysteresis loops of CLAM steel tested with the total strain amplitude of 0.45–1.8%, which was attributed to the dynamic strain aging (DSA) effect. During continuous cyclic deformation, the microstructure and precipitate distribution of CLAM steel changed gradually. Many tempered martensitic laths were decomposed into subgrains, and the size and number of M23C6 carbide and MX carbonitride precipitates decreased with the increase of total strain amplitude. The response cyclic stress promoted the recovery of martensitic lath, while the thermal activation mainly played an important role on the growth of precipitates in CLAM steel at 823 K. In order to have a better understanding of high-temperature LCF behavior, the potential mechanisms controlling stress–strain response, DSA phenomenon and microstructure changes have also been evaluated.

Energy-Aware Rate and Description Allocation Optimized Video Streaming for Mobile D2D Communications

The proliferation problem of video streaming applications and mobile devices has prompted wireless network operators to put more efforts into improving quality of experience (QoE) while saving resources that are needed for high transmission rate and large size of video streaming. To deal with this problem, we propose an energy-aware rate and description allocation optimization method for video streaming in cellular network assisted device-to-device (D2D) communications. In particular, we allocate the optimal bit rate to each layer of video segments and packetize the segments into multiple descriptions with embedded forward error correction (FEC) for realtime streaming without retransmission. Simultaneously, the optimal number of descriptions is allocated to each D2D helper for transmission. The two allocation processes are done according to the access rate of segments, channel state information (CSI) of D2D requester, and remaining energy of helpers, to gain the highest optimization performance. Simulation results demonstrate that our proposed method (named OPT) significantly enhances the performance of video streaming in terms of high QoE and energy saving.

Applications of the generalized Langevin equation: Towards a realistic description of the baths

The generalized Langevin equation (GLE) method, as developed previously [L. Stella et al., Phys. Rev. B 89, 134303 (2014)], is used to calculate the dissipative dynamics of systems described at the atomic level. The GLE scheme goes beyond the commonly used bilinear coupling between the central system and the bath, and permits us to have a realistic description of both the dissipative central system and its surrounding bath. We show how to obtain the vibrational properties of a realistic bath and how to convey such properties into an extended Langevin dynamics by the use of the mapping of the bath vibrational properties onto a set of auxiliary variables. Our calculations for a model of a Lennard-Jones solid show that our GLE scheme provides a stable dynamics, with the dissipative/relaxation processes properly described. The total kinetic energy of the central system always thermalizes toward the expected bath temperature, with appropriate fluctuation around the mean value. More importantly, we obtain a velocity distribution for the individual atoms in the central system which follows the expected canonical distribution at the corresponding temperature. This confirms that both our GLE scheme and our mapping procedure onto an extended Langevin dynamics provide the correct thermostat. We also examined the velocity autocorrelation functions and compare our results with more conventional Langevin dynamics.

A review on completing arsenic biogeochemical cycle: Microbial volatilization of arsines in environment

Arsenic (As) is ubiquitous in the environment in the carcinogenic inorganic forms, posing risks to human health in many parts of the world. Many microorganisms have evolved a series of mechanisms to cope with inorganic arsenic in their growth media such as transforming As compounds into volatile derivatives. Bio-volatilization of As has been suggested to play an important role in global As biogeochemical cycling, and can also be explored as a potential method for arsenic bioremediation. This review aims to provide an overview of the quality and quantity of As volatilization by fungi, bacteria, microalga and protozoans. Arsenic bio-volatilization is influenced by both biotic and abiotic factors that can be manipulated/elucidated for the purpose of As bioremediation. Since As bio-volatilization is a resurgent topic for both biogeochemistry and environmental health, our review serves as a concept paper for future research directions.

Resistance to chemotherapy in ovarian cancer is miRrored by the microRNA miR-433-dependent dysregulation of the cell cycle.

An understanding of the mechanisms underlying the development of resistance to chemotherapy treatment is a gateway to the introduction of novel therapies and improved outcomes for women presenting with ovarian cancer (OC). The desired apoptotic death post-chemotherapy depends on an intact and fully functioning cell cycle machinery.

In this study we demonstrate that stable expression of miR-433 renders OC cells more resistant to paclitaxel treatment. Interestingly, only cells with the highest miR-433 survived paclitaxel suggesting the possible role of miR-433 in cancer recurrence. Importantly, for the first time we demonstrate that miR 433 induces cellular senescence, exemplified by a flattened morphology, the downregulation of phosphorylated Retinoblastoma (p Rb) and increased β galactosidase activity. Surprisingly, miR 433 induced senescence was independent of two well recognised senescent drivers: p21 and p16. Further in silico analysis followed by in vitro experiments identified CKD6 as a novel miR-433 target gene possibly explaining the observed p21 and p16-independent induction of cellular senescence. Another in silico identified miR-433 target gene was CDC27, a protein involved in the regulation of the cell cycle during mitosis. We demonstrate that the overexpression of pre-miR-433 leads to the downregulation of CDC27 in vitro revealing a novel interaction between miR-433 and CDC27, an integral cell cycle regulating protein.

Interestingly, miR-433 expressing cells also demonstrated an ability to impact their tumour microenvironment. We show that miR-433 is present in exosomes released from miR-433 overexpressing and high miR-433 naïve cells. Moreover, growth condition media (GCM) harvested from cells with high miR-433 have higher levels of IL-6 and IL-8, two key cytokines involved in the senescence associated secretory phenotype (SASP). Importantly, GCM from miR-433-enriched cells repressed the growth of co-cultured cells with initial studies showing a GCM-dependent induction of chemoresistance.

In conclusion, data in this study highlights how the aberrant expression miR-433 contributes to chemoresistance in OC cells. We postulate that standard chemotherapy, particularly paclitaxel, used to treat women with OC may have an attenuated ability to kill cells harbouring increased levels of miR-433, allowing for a subsequent chemoresistant phenotype post-therapy.