Subsuming methods: finding new optimisation opportunities in object-oriented software

The majority of existing application profiling techniques ag- gregate and report performance costs by method or call- ing context. Modern large-scale object-oriented applications consist of thousands of methods with complex calling pat- terns. Consequently, when profiled, their performance costs tend to be thinly distributed across many thousands of loca- tions with few easily identifiable optimisation opportunities. However experienced performance engineers know that there are repeated patterns of method calls in the execution of an application that are induced by the libraries, design patterns and coding idioms used in the software. Automati- cally identifying and aggregating costs over these patterns of method calls allows us to identify opportunities to improve performance based on optimising these patterns. We have developed an analysis technique that is able to identify the entry point methods, which we call subsuming methods, of such patterns. Our ofiine analysis runs over previously collected runtime performance data structured in a calling context tree, such as produced by a large number of existing commercial and open source profilers. We have evaluated our approach on the DaCapo bench- mark suite, showing that our analysis significantly reduces the size and complexity of the runtime performance data set, facilitating its comprehension and interpretation. We also demonstrate, with a collection of case studies, that our analysis identifies new optimisation opportunities that can lead to significant performance improvements (from 20% to over 50% improvement in our case studies).

Maximum power point tracking methods for PV systems

Maximum power point tracking (MPPT) is an important consideration in photovoltaic (PV) systems. These systems exhibit variable nonlinear current–voltage (I–V) and power–voltage (P–V) characteristics which vary with environmental conditions. The optimum operation of a PV system occurs when the system operates at the unique maximum power point (MPP) for the given environmental conditions. Key environmental conditions include the irradiance on the cell, temperature of the cell and any shading phenomenon. Shading can occur due to objects, dust or dirt and module mismatch arising from damage or manufacturing tolerances. These shading effects introduce further nonlinearity into the I–V and P–V characteristics of the system. An extensive variety of MPPT techniques has been proposed which vary from simple estimation techniques to advanced tracking techniques. In this chapter, the criteria for assessing the performance of MPPT methods are defined followed by a complete description and discussion of both techniques designed for uniform environmental conditions and those designed for nonuniform environmental conditions.

Comparison of Two Methods for Caluculating the Partition Functions of Various Spatial Statistical Models

Likelihood computation in spatial statistics requires accurate and efficient calculation of the normalizing constant (i.e. partition function) of the Gibbs distribution of the model. Two available methods to calculate the normalizing constant by Markov chain Monte Carlo methods are compared by simulation experiments for an Ising model, a Gaussian Markov field model and a pairwise interaction point field model.

Food security measurement in cultural pluralism : missing the point or conceptual misunderstanding?

Objective : Food Security has become a global concern, yet its measurement has varied considerably across disciplines and countries. We examined the current discrepancies in the definitions of food security and propose a framework for understanding and measuring food security.

Methods : This conceptual review draws from a range of works published in Medline and the gray literature to advance the understanding of food security concepts. We begin by examining the historical background of food security and then move on to examine its various definitions and interpret food through cultural lenses in terms of food access and utilization. We finish by examining various measurements and indicators of food security and reviewing implications for public health.

Results : We argue that the reliance on coping strategies as surrogate measurements of food insecurity without taking into account the social, cultural, and political contexts in which they occur is misleading, and viewing food insecurity solely from a food access or availability perspective, without taking into account food utilization and asset creation as pillars of food security, paints an incomplete picture. Although this review does not claim to provide solutions to the discrepancies in the conceptual definition of food security, it attempts to highlights areas of concern and provide a way forward.

Conclusion : When coping strategies are used as an indicator of food insecurity, they need to be culturally relevant and focus tested, and together with objective measurements of nutritional outcomes, would allow policy makers to make evidence-based decisions to inform social and nutrition policies.

A point-based representation for intervals

Information about time or space is often expressed in terms of points or intervals, and the relations between points and intervals. The interval based representations fall into two distinct classes based on: (i) closure and (ii) minimal representation of the domain. The advantage of closure based representation is the minimal search time at the expense of time to construct the representation, and the storage requirement. Minimal representation optimises storage required, at the expense of construction and search time. Intervals can be represented in terms of their end points. The information about points can be effectively represented using the closure approach but intervals cannot be represented with their endpoints using a point algebra system.

This paper proposes a point based system of representation for interval relations that does not perform closure. Point information is represented in terms of the known relationships between points. The costs of such a representation lies between the expense of closure and minimisation. The time taken for search and construction is better than for minimisation but not as good as for closure. Respectively, the space used is better than for closure but not as good as for minimisation

Patient comfort in the intensive care unit : a multicentre, binational point prevalence study of analgesia, sedation and delirium management

Objective: To measure the prevalence of assessment and management practices for analgesia, sedation and delirium in patients in Australian and New Zealand intensive care units.
Materials and Methods: We developed survey items from a modified Delphi panel and included them in a binational, point prevalence study. We used a standard case report form to capture retrospective patient data on management of analgesia, sedation and delirium at the end of a 4-hour period on the study day. Other data were collected during independent assessment of patient status and medication requirements.
Results: Data were collected on 569 patients in 41 ICUs. Pain assessment was documented in the 4 hours before study observation in 46% of patients. Of 319 assessable patients, 16% had moderate pain and 6% had severe pain. Routine sedation assessment using a scale was recorded in 63% of intubated and ventilated patients. When assessed, 38% were alert and calm, or drowsy and rousable, 22% were lightly to moderately sedated, 31% were deeply sedated (66% of these had a documented indication), and 9% were agitated or restless. Sedatives were titrated to a target level in 42% of patients. Routine assessment of delirium occurred in 3%, and at study assessment 9% had delirium. Wrist or arm restraints were used for 7% of patients.
Conclusions: Only two-thirds of sedated patients had their sedation levels formally assessed, half had pain assessed and very few had formal assessment of delirium. Our description of current practices, and other observational data, may help in planning further research in this area.

Evaluating health services with point of service feedback: perspectives and experiences of patients, staff and community volunteers in an inpatient rehabilitation facility

PURPOSE: To determine patient, staff and community volunteer opinions and experiences of point of service feedback (POSF) in an inpatient rehabilitation facility. METHOD: Participants were recruited by purposeful sampling. Two researchers conducted in-depth semi-scripted interviews with patients, staff or volunteers until no new issues emerged. Manually transcribed interview data underwent thematic analysis that grouped information into categories of related information. RESULTS: Twenty patients, 26 staff from 10 different professional groups, and 2 community volunteers were interviewed. Patient and volunteer data were grouped into five main categories: patients wanted their voice heard and acted on; patients could be positively and negatively affected by POSF; patients could be reluctant to evaluate staff; patients preferred POSF to post-discharge mailed questionnaires; and patients' feedback was influenced by the data collector. Staff wanted: feedback to help them improve the patient experience; and feedback that was trustworthy, usable and used. Staff believed that the feedback-collector influenced patients' feedback and affected how feedback could be used. CONCLUSIONS: Patients, staff and community volunteers identified issues that determine the appropriateness and usefulness of POSF. Policy and practise should address the preferences, needs and experiences of health service users and providers so that POSF produces maximum benefits for both patients and health services. Implications for Rehabilitation POSF can enhance patients' experiences of inpatient rehabilitation by providing a mechanism to be heard and communicating that patients are valued; care must be exercised with patients who find giving feedback stressful. Collecting POSF is most beneficial when coupled with methods to efficiently and effectively respond to feedback. POSF requires interpretation in light of its limitations including patients' ability to accurately and unreservedly communicate their experiences. Who collects POSF requires careful consideration; community volunteers have both advantages and disadvantages.

Maximum power point tracking of partial shaded photovoltaic array using an evolutionary algorithm: a particle swarm optimization technique

 Partial shading is one of the unavoidable complications in the field of solar power generation. Although the most common approach in increasing a photovoltaic (PV) array’s efficiency has always been to introduce a bypass diode to the said array, this poses another problem in the form of multi-peaks curves whenever the modules are partially shaded. To further complicate matters, most conventional Maximum Power Point Tracking methods develop errors under certain circumstances (for example, they detect the local Maximum Power Point (MPP) instead of the global MPP) and reduce the efficiency of PV systems even further. Presently, much research has been undertaken to improve upon them. This study aims to employ an evolutionary algorithm technique, also known as particle swarm optimization, in MPP detection. VC 2014 Author(s).

A comparative study on procedure and state of the art of conventional maximum power point tracking techniques for photovoltaic system

Due to the increasing world energy demand, renewable energy systems have been significantly applied in the power generation sector. Among the renewable energy options, photovoltaic system is one of the most popular resources which has been experiencing a huge attention during recent decades. The remarkable advantages, such as static and movement free characteristics, low maintenance costs, and longevity are the primary factors for the popularity of solar generation in the late years. Nevertheless, the low PV conversion efficiency in one side and high PV material cost in the other side have made PV generation comparably expensive system. Consequently, a capable maximum power point tracking (MPPT) is all important to elicit the maximum energy from the production of PV systems. Different researches have been conducted to design a fast, simple and robust MPPT technique under uniform conditions. However, due to the series and parallel connection of PV modules and according to the use of bypass diodes, in the structure of PV modules, a conventional techniques are unable to track a true MPP. Recently, several studies have been undertaken to modify these conventional methods and enable them to track the global MPP under rapidly changing environments and partial shading (PS) conditions. This report concentrates on the state of the art of these methods and their evolution to apply under PS conditions. The recent developments and modifications are analyzed through a comparison based on design complexity, cost, speed and the ability to track the MPP under rapid environmental variations and PS conditions.

A novel approach to needs assessment in curriculum development: going beyond consensus methods

BACKGROUND: Needs assessment should be the starting point for curriculum development. In medical education, expert opinion and consensus methods are commonly employed. AIM: This paper showcases a more practice-grounded needs assessment approach. METHODS: A mixed-methods approach, incorporating a national survey, practice audit, and expert consensus, was developed and piloted in thrombosis medicine; Phase 1: National survey of practicing consultants, Phase 2: Practice audit of consult service at a large academic centre and Phase 3: Focus group and modified Delphi techniques vetting Phase 1 and 2 findings. RESULTS: Phase 1 provided information on active curricula, training and practice patterns of consultants, and volume and variety of thrombosis consults. Phase 2's practice audit provided empirical data on the characteristics of thrombosis consults and their associated learning issues. Phase 3 generated consensus on a final curricular topic list and explored issues regarding curriculum delivery and accreditation. CONCLUSIONS: This approach offered a means of validating expert and consensus derived curricular content by incorporating a novel practice audit. By using this approach we were able to identify gaps in training programs and barriers to curriculum development. This approach to curriculum development can be applied to other postgraduate programs.

Health services should collect feedback from inpatients at the point of service: opinions from patients and staff in acute and subacute facilities

OBJECTIVE: Point of service feedback (POSF) enables patients to give health services feedback about their experiences during or immediately after care. Despite the increasing use of POSF, little is known regarding patients' and staffs' opinions of this practice and whether they consider it acceptable or useful. The study aimed to determine patient and staff opinions regarding POSF. DESIGN: A cross-sectional survey. SETTING: Acute and subacute healthcare facilities. PARTICIPANTS: Two hundred and forty-seven patients and 221 staff. RESULTS: Participants indicated that patients should be invited to evaluate health services when they are in hospital or subacute care and improving services was the most important reason for doing so. Staff indicated that:• collecting patients' feedback during their stay was an important part of providing care and not an interruption to it (n = 187 of 221, 85%).• collecting patients' feedback was best done with a variety of methods; talking directly with patients during their stay was the preferred option (n = 161 of 219, 74%).More patients preferred to:• give feedback during their stay (51%) than after discharge from care (15%).• give feedback by talking with someone (45%) than completing a questionnaire (31%).Some patients (14%) were concerned about reprisal from staff if they gave negative feedback. CONCLUSIONS: POSF can be acceptable and useful for evaluating health services and should be incorporated into a person-centred approach that allows patients to choose from a variety of feedback options both during and after their stay. To be most useful, feedback should be incorporated into a quality improvement system.

Dynamic access point association using software defined networking

Previous attempts in addressing Access Point (AP) association at overlapping zone of IEEE 802.11 networks have shown some issues. They work passively and estimate load from different network metrics such as frame delay, packet loss, number of users etc. that may not always true. Further the user behaviour is selfish i.e. illegitimate user consume high network resources. This adversely affect existing or new users which in turn motivates them to change locations. To alleviate these issues, we propose the use of a Software Defined Networking (SDN) enabled client side (wireless end user) solution. In this paper, we start by proposing a dynamic AP selection algorithm/framework in wireless user device. The device receive network resource related statistics from SDN Controller and guide the client device to associate itself with the best selected AP. We justify that the use of SDN discourage users to act selfishly. Further, a mathematical modelling of the proposed scheme is derived using Fuzzy membership function and the simulation is carried out. Results obtained from simulation necessitates to implement SDN enabled client side methods.

Switch point finding using polynomial regression for fuzzy type reduction algorithms

Karnik-Mendel (KM) algorithm is the most widely used type reduction (TR) method in literature for the design of interval type-2 fuzzy logic systems (IT2FLS). Its iterative nature for finding left and right switch points is its Achilles heel. Despite a decade of research, none of the alternative TR methods offer uncertainty measures equivalent to KM algorithm. This paper takes a data-driven approach to tackle the computational burden of this algorithm while keeping its key features. We propose a regression method to approximate left and right switch points found by KM algorithm. Approximator only uses the firing intervals, rnles centroids, and FLS strnctural features as inputs. Once training is done, it can precisely approximate the left and right switch points through basic vector multiplications. Comprehensive simulation results demonstrate that the approximation accuracy for a wide variety of FLSs is 100%. Flexibility, ease of implementation, and speed are other features of the proposed method.