A New Hybrid Scheduling Framework for Asymmetric Wireless Environments with Request Repetition

The essence of efficient scheduling and data transmission techniques lies in providing the Web-applications with advanced data processing capabilities. In this paper we have efficiently combined the push and the pull scheduling to develop a new, practical, dynamic, hybrid scheduling strategy for heterogenous, asymmetric environments. The proposed algorithm dynamically computes the probabilities and the optimal cutoff-point to separate the push and the pull data sets. The data items are also assumed to be of variable lengths. While the push strategy uses the flat, round-robin scheduling, the pull items are determined by stretch-optimal (max-request min-service time) scheduling policy. In order to make the scheduling more practical, we have considered the impact of the impatience of the clients waiting to get the service of a particular data item. The effects of this impatience can lead to departure of specific client(s) from the system. Our proposed hybrid scheduling strategy takes care of these effects to capture a real portrayal of the system dynamics. These scenarios are modelled by suitable birth and death process to analyze the overall expected delay of the system. Subsequently, simulation results corroborate the average system performance and points out significant improvement over existing hybrid systems in terms of average waiting time spent by a client.

It is believed that broadcast is an efficient way to transmit data in an asymmetric communication system. Most of the previous work focused on either pull-based or push-based scheduling. However, for systems with a very large number of data items, none of these schemes is efficient individually. We propose a novel hybrid scheduling algorithm which uses both pull- and push-based schemes. In our approach, data items are divided, by a suitable cut-off point, into two disjoint sets: one consisting of more-popular items and the other of less-popular items. The items in the former set are broadcast by a push-based schedule, while those in the latter set by a pull-based schedule. A cut-off point is said to be optimal when it minimizes the expected access time in the system. The optimal cut-off point is derived analytically and validated by simulation experiments. Results show that the proposed hybrid push- and pull-based scheduling performs always better than a pure push-based scheduling and improves on the expected access time of an existing hybrid scheduling scheme.

The rapid growth of web services has already given birth to a set of data dissemination applications. Efficient scheduling techniques are necessary to endow such applications with advanced data processing capability. In this paper, we have developed a new hybrid scheduling scheme by effectively combining broadcasting of very popular (push) data and dissemination of less popular (pull) data to develop a new, ideal hybrid scheduling scheme. Our algorithm assumes no prior knowledge of the data access probability, i.e. which items are being pushed or pulled. Instead, data access probabilities and the cut-off-point to segregate the push and the pull sets are computed dynamically. The data items are assumed to be of variable lengths. The clients send their requests to the server, which ignores the requests for the push items but queues those for the pull items. An ideal behavior of the clients is assumed: a client, after making a request, patiently waits without taking any action. Every client is assumed to have a priority. The priority of a data item is determined by adding the priorities of all the clients requesting that item. At every instant, the item to be broadcast is selected with the help of a pure-push scheduling. On the other hand, the item to be pulled is the one stored in the pull-queue, having the optimal stretch value (max-request min-service time). When more than one data item has the same stretch value, the influence of the priorities of different clients on data dissemination is considered. A suitable modelling technique using the birth-and-death process is developed to analyze the performance of the system. Simulation results corroborate the average system performance and exhibit significant improvement over a pure push and existing hybrid systems in terms of average waiting time spent by a client.

Many different digital learning environments are currently in use. In combination with virtual reality (VR) technologies, these allow the creation of engaging hands-on experiences. While VR environments can deeply immerse the person wearing the headset, spectators are often not actively involved or are not even considered in the design phase. This is an issue for learning environments, as learning often takes place in pairs or groups. We propose a novel system that enables more than one person to join the VR world in a co-located space to overcome this problem. In addition to the classic VR headset, the asymmetric VR system features a position-tracked tablet. To evaluate this asymmetric VR concept, we conducted a study with 14 students to explore the user experience and motivation, the social presence, and possible further fields of application. The results indicate that users in both perspectives feel that they can control the virtual world.

Environmental issues and the need to reduce energy consumption for lowering operating costs have pushed power efficiency to become one of the major issues of current research in the field of wireless networks. This paper addresses a number of multiple input multiple output (MIMO) precoding and scheduling techniques across the PHY and MAC layers that can operate under a reduced link budget and collectively improve the transmit power efficiency of a base station, while maintaining the same levels of service. Different MIMO transmission and precoding schemes proposed for LTE, achieving varying degrees of multiuser diversity in both the time, frequency as well as the space domain, are examined. Several fairness-aware resource allocation algorithms are applied to the considered MIMO schemes and a detailed analysis of the tradeoffs between power efficiency and quality of service is presented. This paper explicitly examines the performance of a system serving real-time, VoIP traffic under different traffic loading conditions and transmit power levels. It is demonstrated that by use of efficient scheduling and resource allocation techniques significant savings in terms of consumed energy can be achieved, without compromising QoS.

To improve understanding of afferent limb behaviour in acute hospital ward settings, to define and specify who needs to do what differently and to report what afferent limb behaviours should be targeted in a subsequent multi-phase, theory-based, intervention development process. Focused ethnography was used including direct observation of nursing staff enacting afferent limb behaviours and review of vital signs charts. An observation guide focused observation on "key moments" of the afferent limb. Descriptions of observations from between 7 January 2019-18 December 2019 were recorded in a field journal alongside reflexive notes. Vital signs and early warning scores from charts were reviewed and recorded. Field notes were analysed using structured content analysis. Observed behaviour was compared with expected (policy-specified) behaviour. Observation was conducted for 300hr. Four hundred and ninety-nine items of data (e.g., an episode of observation or a set of vital signs) were collected. Two hundred and eighty-nine (58%) items of data were associated with expected (i.e. policy-specified) afferent limb behaviour; 210 (42%) items of data were associated with unexpected afferent limb behaviour (i.e. alternative behaviour or no behaviour). Ten specific behaviours were identified where the behaviour observed deviated (negatively) from policy or where no action was taken when it should have been. One further behaviour was seen to expedite the assessment of a deteriorating patient by an appropriate responder and was therefore considered a positive deviance. Afferent limb failure has been described as a problem of inconsistent staff behaviour. Eleven potential target behaviours for change are reported and specified using a published framework. Clear specification of target behaviour will allow further enquiry into the determinants of these behaviours and the development of a theory-based intervention that is more likely to result in behaviour change and can be tested empirically in future research.

Screening and case finding for major depressive disorder using the Patient Health Questionnaire (PHQ-9): a meta-analysis

Various methods for mapping signal processing algorithms into systolic arrays have been developed in the past few years. In this paper, efficient scheduling techniques are developed for the partitioning problem, i.e. problems with size that do not match the array size. In particular, scheduling for the Locally Parallel-Globally Sequential (LPGS) technique and the Locally Sequential-Globally Parallel (LSGP) technique are developed. The scheduling procedure developed exploits the fact that after LPGS and LSGP partitioning, the locality constraints are less stringent allowing for more flexibility in the choice of algorithms and inter-processor communication. A flexible scheduling order is developed that is useful in evaluating the trade-off between execution time and size of storage buffers. The benefits of the scheduling techniques are illustrated with the help of matrix multiplication and least squares examples.

There is little agreement as to the optimal cutoff point for thyrotropin testing in primary thyroxine screening programs for congenital hypothyroidism. Most programs in the United States use a cutoff point of 10% of the lowest thyroxine values, whereas in the Netherlands a cutoff point of 20% is used. Therefore, the results of the Dutch program may provide valuable information about the optimal cutoff point. The frequency distribution of screening thyroxine values was studied in all cases of permanent primary congenital hypothyroidism (n = 481) detected in 1,601,603 screened children born during the period from January 1, 1981, to December 31, 1989, in the Netherlands. Programs using a 10% cutoff point would have missed 1.5% of cases. Above the 10% cutoff point, the marginal costs increase quite rapidly because of the escalating numbers of thyrotropin measurements necessary to detect one case of permanent primary congenital hypothyroidism: 20,000 in the range of 11% to 15% and 40,000 in the range of 16% to 20%. Based on these findings, a cutoff point of at least 10% is recommended.

To identify optimal cut-off points of fasting plasma glucose for two-step strategy in screening of undiagnosed diabetes in Chinese people, data were selected from two cross-sectional studies of Metabolic Syndrome in Zhejiang Province of China, Zhejiang Statistical Yearbook (2010), and published literatures. Two-step strategy was used among 17437 subjects sampled from population to screen undiagnosed diabetes. Effectiveness (proportion of cases identified), costs (including medical and non-medical costs), and efficiency (cost per case identified) of these different two-step screening strategies were evaluated. This study found the sensitivities of all the two-step screening strategies with further Oral Glucose Tolerance Test (OGTT) at different Fasting Plasma Glucose (FPG) cut-off points from 5.0 to 7.0 (mmol/L) ranged from 0.66 to 0.91. For the FPG point of 5.0 mmol/L, 91 percent of undiagnosed cases were identified. The total cost of detecting one undiagnosed diabetes case ranged from 547.1 to 1294.5 CNY/case, and the strategy with FPG at cut-off point of 6.1 (mmol/L) resulted in the least cost. Considering both sensitivity and cost of screening diabetes, FPG cut-off point at 5.4 mmol/L was optimized for the two-step strategy. In conclusion, different optimal cut-off points of FPG for two-step strategy in screening of undiagnosed diabetes should be used for different screening purposes.

In a P2P network, it is common that data items are replicated on multiple peers for improving data availability. In such an environment, when a data item is updated on a particular peer, the update should be immediately propagated to other peers holding its replicas. However, in some applications, some replica holders do not need the update when the degree of change in the update is small. In this paper, we propose two update propagation strategies considering the degree of change in data update in P2P networks. Our proposed strategies reduce the load for propagating data update by suppressing the update propagation to replica holders which do not need to receive the update. Moreover, we verify the effectiveness of our strategies by simulation experiments.

The purpose of this paper was to establish the diagnostic value of the C-reactive protein measurement (CRP) in patients attending their general practitioner (GP) with a new complaint for which the GP considers determination of the erythrocyte sedimentation rate (ESR) to be indicated. During 4 successive months in 1992, 11 GPs in four general practice centres in the Netherlands identified patients indicated for the erythrocyte sedimentation rate. ESR and CRP were determined at the local hospital laboratory. One year later, an independent GP established the follow-up diagnoses. By comparing the test results with the follow-up diagnoses, using logistic regression analysis and Receiver Operating Characteristic curves, sensitivities, specificities, predictive values and odds ratios were established. In 396 patients the prevalence of inflammatory diseases and malignancies ('pathology') was found to be 26% in males and 15% in females. Both ESR and CRP were valuable in discriminating pathology from harmless, often self-limiting diseases. The optimal upper limits of reference values ('cut-off points') for ESR were found to be 31 mm in both males and females. At these cut-off points, the diagnostic gains from positive and negative test results (positive predictive value minus prevalence, and negative predictive value minus 100% minus prevalence) were 45% and 4% for males and 30% and 2% for females. The optimal cut-off point for CRP was found at 15 mg L-1 in males and 34 mg L-1 in females. The diagnostic gain from positive and negative test results were 18% and 9% in males and 25% and 4% in females.(ABSTRACT TRUNCATED AT 250 WORDS)

ObjectivesThe Patient Health Questionnaire (PHQ) and Generalised Anxiety Disorder Scale (GAD) are widely used screening tools, but their sensitivity and specificity in low-income and middle-income countries are lower than in...

BackgroundWe sought to establish the optimal waist circumference (WC) cut-off point for predicting diabetes mellitus (DM) and to compare the predictive ability of the metabolic syndrome (MetS) criteria of the Joint Interim Statement (JIS) and the Japanese Committee of the Criteria for MetS (JCCMS) for DM in Japanese.MethodsParticipants of the Japan Epidemiology Collaboration on Occupational Health Study, who were aged 20–69 years and free of DM at baseline (n = 54,980), were followed-up for a maximum of 6 years. Time-dependent receiver operating characteristic analysis was used to determine the optimal cut-off points of WC for predicting DM. Time-dependent sensitivity, specificity, and positive and negative predictive values for the prediction of DM were compared between the JIS and JCCMS MetS criteria.ResultsDuring 234,926 person-years of follow-up, 3180 individuals developed DM. Receiver operating characteristic analysis suggested that the most suitable cut-off point of WC for predicting incident DM was 85 cm for men and 80 cm for women. MetS was associated with 3–4 times increased hazard for developing DM in men and 7–9 times in women. Of the MetS criteria tested, the JIS criteria using our proposed WC cut-off points (85 cm for men and 80 cm for women) had the highest sensitivity (54.5 % for men and 43.5 % for women) for predicting DM. The sensitivity and specificity of the JCCMS MetS criteria were ~37.7 and 98.9 %, respectively.ConclusionData from the present large cohort of workers suggest that WC cut-offs of 85 cm for men and 80 cm for women may be appropriate for predicting DM for Japanese. The JIS criteria can detect more people who later develop DM than does the JCCMS criteria.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-2856-9) contains supplementary material, which is available to authorized users.

The upcoming wireless LAN standard IEEE 802.11ac extends the channel bandwidth from conventional 20 or 40 MHz to 80 or 160 MHz to increase the data rate. Consequently, there could be stations supporting different channel bandwidths in one area. Stations belonging to the same basic service set (BSS) have to operate on the primary channel, which is a common 20 MHz sub-channel. In such a situation, the secondary channels associated with the primary channel may remain unused and, as a result, the system capacity will be degraded. To address this problem, we propose a multi-user multi-channel transmission technique to improve the efficiency of downlink transmissions. The computer simulation results confirm the effectiveness of the proposed method.