Mobile Peers Research Articles

SPF-A*: Searching Multimedia Data in Heterogeneous Mobile P2P Network

Mobile P2P (MP2P) network has been widely used in everyday life combined with the wireless technology development. However, most previous works concentrate on the assumption that the mobile peers are identical of their inner properties in compositing a MP2P network. However, in current network environment, heterogeneous devices are widely used; they may have different storage sizes, data transmission rate, processing ability and even security levels. In such kind of MP2P Network environment, how to make data transmission effectively is challenge. In this paper, we concentrate on how to effectively obtain a queried multimedia resource and generate a path for such data transmission on the overlay MP2P network, so as to make the resource more effectively transmit among the heterogeneous peers. A new path generating algorithm called SPF-A* (Super Peer First A*) is devised, and simulation studies are conducted to validate our proposal.

Editorial: Special issue on mobile P2P networking and computing

Peer-to-Peer networking first emerged as an overlay technique to support distributed file sharing over the Internet. Since then, P2P networking and computing have gradually evolved into a system framework that delivers a broad range of distributed and scalable resource discovery and sharing applications including efficient search of data items and people using context/key based routing, application level multicast, redundant storage, video streaming, etc. Striving for automated formation, distributed operation and effective resource sharing, peers form self-organizing overlay networks and offer services beyond the traditional client-server paradigm of Internet by entrusting symmetry in roles and requiring no or fewer pre-established servers. Today, mobile end devices are one of the major participants in information gathering, processing, dissemination and consumption. Supporting the P2P networking and computing paradigm in this ever growing mobile communications environment has become an appealing idea. The key attraction of the Mobile P2P (MP2P) paradigm is its ability to scale without requiring expensive and manually configured servers, and to sustain failure points through automatic recovery of a fully distributed structure. Compared with wired networks, it is generally more difficult to set up and maintain centralized servers in some mobile networks, such as in the Mobile Ad hoc Network (MANET). It may also be generally possible to harvest efficiency gains through sharing applications and contents among peer mobile end devices directly rather than backhauling them to a centralized server in the fixed backbone network. Though the P2P paradigm may naturally suit well the distributed and dynamic wireless communications environment, support of MP2P is particularly challenging considering the special characteristics of the mobile networks. The highly variable connectivity, frequent disconnection, locationdependency, energy and resource constraints, diversity in wireless end devices and as well the carrier-grade performance requirements when offering business level applications bring about some critical issues in facilitating the MP2P paradigm. The mobility of the users may increase dramatically the churn in the peer systems to engender extra overhead when employing P2P overlay protocols. The limited bandwidth and constrained battery resource available to the wireless device aggravate the hindrance and may even render the P2P overlay mechanism infeasible in operation. Due to resource limitations, mobile peers can be inclined to the selfish freerider behaviour in data sharing and downloading. The Peer-to-Peer Netw Appl (2009) 2:179–181 DOI 10.1007/s12083-009-0040-z

An economic incentive model for encouraging peer collaboration in mobile-P2P networks with support for constraint queries

In mobile ad hoc peer-to-peer (M-P2P) networks, economic models become a necessity for enticing non-cooperative mobile peers to provide service. M-P2P users may issue queries with varying constraints on query response time, data quality of results and trustworthiness of the data source. Hence, we propose ConQuer, which is an economic incentive model for the efficient processing of constraint queries in M-P2P networks. ConQuer also provides incentives for peer collaboration in order to improve data availability. The main contributions of ConQuer are three-fold. First, it uses a broker-based economic M-P2P model for processing constraint queries via a Vickrey auction mechanism. Second, it proposes the CR*-tree, a dynamic multidimensional R-tree-based index for constraints of data quality, trust and price of data to determine target peers efficiently. The CR*-tree is hosted by brokers, who can sell it to other peers, thereby encouraging the creation of multiple copies of the index for facilitating routing. Third, it provides incentives for peers to form collaborative peer groups for maximizing data availability and revenues by mutually allocating and deallocating data items using royalty-based revenue-sharing. Such reallocations facilitate better data quality, thereby further increasing peer revenues. Our performance study shows that ConQuer is indeed effective in answering constraint queries with improved response time, success rate and data quality, and querying hop-counts.

콘텐츠 검색 서비스를 위한 효율적인 이동 P2P 구조

본 논문에서는 이동 피어의 콘텐츠 탐색을 효율적으로 지원할 수 있는 이동 P2P 구조를 제안한다. 제안하는 이동 P2P 구조는 이동 피어의 탐색 비용을 감소시키기 위해 이동 피어, 이동 슈퍼 피어, 고정 슈퍼 피어로 구성된 3계층 구조이다. 이동 피어가 콘텐츠 탐색을 수행하기 위해서는 통신 가능한 피어로부터 콘텐츠를 찾고 질의영역 확장을 위해 이동 슈퍼 피어, 고정 슈퍼 피어를 이용한 계층적 콘텐츠 탐색을 수행한다. 계층적 콘텐츠 탐색, 피어 이동성에 따른 서비스 연속성을 보장하기 위해 이동 피어의 가입/탈퇴 과정은 이동성을 지원하는 메시지 구조에 의해 명시적으로 상위 피어에 저장한다. 실험 평가 결과 제안하는 구조는 기존의 2계층 구조 보다 콘텐츠 탐색 속도가 약 32% 향상되었고 고정 슈퍼 피어로 전송되는 메시지를 감소시켜 고정 슈퍼 피어 탐색 부하를 약 25% 감소시켰다. In this paper, we propose the mobile P2P structure supporting content searches for mobile peers efficiently. The proposed mobile P2P structure is a 3-tier structure which consists of a mobile peer, a mobile super peer, and a stationary super peer to reduce the content search cost of mobile P2P service. For content searches, mobile peer searches content in the communication range and performs hierarchical content searches which is using mobile super peer, stationary super peer for expansion of query region. In order to support hierarchial content searches and the continuity of services according to peer mobilities, peer's join/leave processes are explicitly stored by supporting message structures to the upper layer It is shown through experimental evaluation that the proposed structure improves about 32% contents search performance over the existing 2-tier structure. Since it also reduces the messages transferred to the stationary super peers, it reduced about 25% search loads of them.

AAPP: An Anycast Based AODV Routing Protocol for Peer to Peer Services in MANET

The study of Peer-to-Peer (P2P) network and Mobile Ad hoc Network (MANET) are currently two hotspots in distributed domain. We propose a novel anycast based AODV routing protocol which is a simple and efficient routing protocol designed especially for MANET for P2P applications called AAPP (an Anycast based AODV routing protocol for Peer to Peer services in MANET). AAPP integrate DHT protocol operating in a logical namespace and MANET routing protocol operating in a physical namespace. The key idea of the integration is to bring the Chord protocol to the network layer of MANETs via a one-to-one mapping between the service keys of the mobile nodes providing services and their anycast groupIDs in the namespace. The object of our design is to construct a new type of anycast based AODV model for P2P services, especially for discovery service, information administration service, file sharing service, and communication security. It is assumed that the number of anycast groups is steady in a MANET, so we consider the instance that a node joins or leaves an anycast group. When a mobile node attains a service, such as a file and a particular data, it can share its resource to other nodes and becomes a mobile peer. Whenever a mobile node joins or leaves an anycast group, it originates a request packet and sends it to the network layer. The anycast groupID is updated correspondingly, and broadcasts the information about updating information. In this paper, we have designed an anycast based protocol for P2P application in mobile wireless ad hoc networks based on on-demand routing protocols AODV. We have tested the packets' delivery fraction, average end-to end delay of data packets, and normalized the routing protocol performance of anycast protocols by simulation with OPNET on different traffic models, node mobility models, and connection models. With our novel anycast protocol AAPP, the traffic load can be balanced thus, reducing the transmission delay and increase the route utilization which is better for P2P application. That all the members in one anycast group share one anycast address enables them to take the same priority in the routing searching process. Therefore, this approach can provide the transmission path with the shortest length. With scattering of the anycast server in the geographical area, the traffic load is obviously distributed in the network. All these properties can help to improve the performance of the network.

Secure offline superdistribution for mobile platforms

Superdistribution and other peer-to-peer (P2P) distribution schemes like sharing or rental offer a flexible and user-friendly way to distribute digital content. However, the parties involved have different interests (e.g. user privacy vs. license enforcement) that should be reflected in the underlying security architecture. We identify characteristic P2P scenarios and demonstrate how these can be realised by applying a few basic licensing operations. We then present a security architecture to realise these basic license operations (1) in a generalised fashion and (2) employing the ARM TrustZone technology, which will be used in many future mobile platforms. Further, we extend existing superdistribution schemes for offline application, allowing a mobile peer to access superdistributed content without the need to first contact the actual licenser.

Data Fusion and Aggregation Methods for Pre-Processing Ambulatory Monitoring and Remote Sensor Data for Upload to Personal Electronic Health Records

Peer-to-Peer (P2P) applications are becoming more prevalent in mobile 3G/4G devices. Categorized as collaborative P2P applications, MSN, ICQ and Yahoo IM are in use for years, while recently, filesharing P2P applications like Nokia mBit and PeerBox have also been introduced. Contemporary mobile peers are capable of sharing P2P content using Bluetooth technology i.e. bypassing cellular vendor’s network altogether. Mobile devices are resource constrained in terms of memory and processing thus security threats like scanning and non-scanning worms could result in choking these resources. 3G/4G mobile devices come equipped with no significant software for detection of such an immense threat and hence, worms could exploit vulnerabilities to cause catastrophes. Worms are capable of propagation through mobile P2P networks using three known approaches; content sharing using cellular vendor’s network, through Bluetooth communication directly among different peers and through MMS and SMS messaging. Authors have come up with distinctive ideas to deal with such threats, however, most of them focus solely on one way of threat propagation at any instance of time, unrealistically discarding all other windows of threat propagation. Some approaches target only one specific worm or worm behaviour. There have been over four hundred mobile P2P worms discovered so far and hence the scope of current detection mechanisms comes to literally a nought. We bring in a unified framework for worm detection & throttling in mobile P2P networks that deals with epidemiological spreading of worms through all three windows of propagation. Solution delegates guardian nodes in the network to throttle worms once detected through collaborative information sharing between mobile devices and the guardian nodes. It targets different types of worm behaviours, hence giving it a significant edge over previous approaches. By employing artificial intelligence techniques, the framework can adapt to tackle ever-evolving worm attack strategies.

UP2P: a peer-to-peer overlay architecture for ubiquitous communications and networking

Approaches to building an intelligent consumer-friendly network have evolved over time from centralized switch-based to router- and server-based Internet architectures. We propose to drive this evolution further with a new highly scalable architecture that provides features to users derived from the computational and networking capabilities of very large populations of sophisticated terminals. This architecture relies on emerging peer-to-peer overlay technology. We describe a peer-to-peer overlay design that addresses requirements crucial for consumer applications, including overlay federation, peer heterogeneity, peer mobility, and service discovery. In addition, we introduce the concept of an overlay operator and describe the requirements for managed overlays. We have designed and implemented both a middleware and a peer-topeer platform that illustrates these concepts.

Cooperative incentive mechanism based on game theory in mobile P2P networks

Many selfish mobile peers consume much resource without any contribution in mobile P2P network.Considering the limitation of network resource and selfishness of peers,this paper proposed a cooperative incentive mechanism based on game theory.The mechanism provided peers with different network's service quality according to their contribution and therefore every peer was encouraged to cooperate with others or share their resource.This paper described and analyzed the resource allocation policy of cooperative incentive mechanism in detail.Besides,the existence of the steady Nash equilibrium in the game was also proven.Simulation and analysis results show that the incentive mechanism can encourage the cooperation among the peers and improve the network performance efficiently.Compared with current cooperative incentive mechanism,the mechanism can increase forwarding ratio of the packet.

Location-Based Spatial Query Processing with Data Sharing in Wireless Broadcast Environments

Location-based spatial queries (LBSQs) refer to spatial queries whose answers rely on the location of the inquirer. Efficient processing of LBSQs is of critical importance with the ever-increasing deployment and use of mobile technologies. We show that LBSQs have certain unique characteristics that traditional spatial query processing in centralized databases does not address. For example, a significant challenge is presented by wireless broadcasting environments, which have excellent scalability but often exhibit high-latency database access. In this paper, we present a novel query processing technique that, while maintaining high scalability and accuracy, manages to reduce the latency considerably in answering location-based spatial queries. Our approach is based on peer-topeer sharing, which enables us to process queries without delay at a mobile host by using query results cached in its neighboring mobile peers. We demonstrate the feasibility of our approach through a probabilistic analysis, and we illustrate the appeal of our technique through extensive simulation results.

Effect of a community-based delivery of intermittent preventive treatment of malaria in pregnancy on treatment seeking for malaria at health units in Uganda

The impact of intermittent preventive treatment (IPTp) on malaria in pregnancy is well known. However, in countries where this policy is implemented, poor access and low compliance have been widely reported. Novel approaches are needed to deliver this intervention. To assess whether traditional birth attendants, drug-shop vendors, community reproductive health workers and adolescent peer mobilizers can administer IPTp with sulphadoxine-pyrimethamine (SP) to pregnant women, reach those at greatest risk of malaria, and increase access and compliance with IPTp. An intervention study compared the delivery of IPTp in the community with routine delivery of IPTp at health units. The primary outcome measures were the proportion of adolescents and primigravidae accessed, and the proportion of women who received two doses of SP. The study also assessed the effect of the intervention on access to malaria treatment, antenatal care, other services and related costs. More women (67.5%) received two doses of SP through the community approach compared with health units (39.9%; P<0.0001). Women who accessed IPTp in the community were at an earlier stage of pregnancy (21.0 weeks of gestation) than women who accessed IPTp at health units (23.1 weeks of gestation; P<0.0001). However, health units were visited by a higher proportion of primigravidae (23.6% vs 20.0%; P<0.04) and adolescents (28.4% vs 25.0%; P<0.03). Generally, women who accessed IPTp at health units made more visits for malaria treatment (2.6 (1.0-4.7) vs 1.8 (1.4-2.2); P<0.03). At recruitment, more women who accessed IPTp at health units sought malaria treatment compared with those who accessed IPTp in the community (56.9% vs 49.2%). However, at delivery, a high proportion of women who accessed IPTp in the community had sought malaria treatment (70.3%), suggesting the possibility that the novel approach had a positive impact on care seeking for malaria. Similarly, utilization of antenatal care, insecticide-treated nets and delivery care by women in the community was high. The total costs per woman receiving two doses of SP for IPTp were 4093 Uganda shillings (US$ 2.3) for women who accessed IPTp at health units, and 4491 Uganda shillings (US$ 2.6) for women who accessed IPTp in the community. The community approach was effective for the delivery of IPTp, although women still accessed and benefited from malaria treatment and other services at health units. However, the costs for accessing malaria treatment and other services are high and could be a limiting factor in mitigating the burden of malaria in Uganda.

Letter to the Editor: Responding to the Human Resource Crisis: Peer Health Workers, Mobile Phones, and HIV Care in Rakai, Uganda.

Dear Editor: Two challenges to successful antiretroviral therapy (ART) scale-up in resource-limited settings (RLS) are human resource and healthcare infrastructure limitations.1 We read with interest the modeling study by Barnighausen et al. which describes the complexities of ensuring adequate human resources to treat HIV/AIDS (HRHA).2 The authors suggest that factors needed to achieve universal ART coverage include “changes in the nature or organization of care,” training health workers with skills specific to the developing world to reduce emigration, and developing systems that decrease the number of traditional HRHA required to treat a fixed number of patients. The Rakai Health Sciences Program (RHSP) PEPFAR-funded ART program has been actively pursuing innovative HIV care strategies that directly address these important points. In 2006, we piloted a novel program utilizing peer health workers (PHW) and mobile phones to monitor patients in a rural ART program in Rakai, Uganda. In May 2006, the RHSP ART program recruited and trained nineteen PHWs. These PHWs are persons living with HIV themselves and receiving care through the program. Each PHW was assigned approximately 15–20 patients with whom they would typically conduct biweekly home visits. At visits, PHWs documented a review of symptoms (headache, fever, etc.), a missed pills by self-report, and a pill count, along with providing adherence counseling, health education, and social support. Documentation was returned to higher-trained providers for review and triage. PHWs were supplied bikes, identifying t-shirts, and compensation for part-time employment. Over a 6-month pilot period, PHWs completed documentation on 3,642 home visits (approximately 7.5 visits per PHW per week). Nine PHWs were additionally trained to use mobile phones to send real-time text messages containing clinical and adherence data to higher-trained providers for review and triage. These texts were numeric codes produced by converting home visit data, e.g., yes=1, no=0. PHWs could also place calls to a central toll-free clinic phone with any concerns. Due to limited electrical power, a lead-acid battery system was used to charge phones. All technology used was available in-country. These nine PHWs successfully sent 1,177 text messages (approximately 5 per PHW per week) over the pilot period. PHWs also made 101 calls to the central clinic over the study period, mostly for guidance on illnesses, urgent care needs, and concerns about drug side effects. A Likert scale (1–5, 1=strongly agree, 5=strongly disagree) survey administered to 39 PEPFAR clinical staff (response rate = 100%) found 44% (17/39) strongly agreed and 56% (22/39) agreed that the PHW and mobile phone intervention had improved the overall health of patients; 20% (8/39) strongly agreed and 49% (19/39) agreed it had improved patient adherence. Direct per PHW program startup costs were approximately $115 USD with monthly maintenance costs approximately $15 USD. The mobile phone intervention per PHW startup costs were an additional $100 USD with monthly maintenance costs of approximately $10 USD. We found that a simple and inexpensive clinical and adherence monitoring intervention leveraging PHWs empowered with mobile phones could be successfully implemented in a rural RLS. PHWs are currently an underutilized resource which may provide one solution to increasing HRHA.3 As the numbers of potential PHWs are inherently related to the prevalence of HIV, these individuals represent a flexible and sustainable work force that is unlikely to emigrate and able to remain proportional in size to the epidemic. This PHW work force can concentrate its efforts on monitoring and supporting patients on ART, while the limited number of more highly trained health workers (e.g., nurses and clinical and medical officers) can focus their time on more clinically demanding tasks. Further operations research is needed to better understand PHW effects on HIV care outcomes, which responsibilities are appropriate to task-shift to PHWs, determine acceptable training and evaluation standards, assess cost-effectiveness, and evaluate the sustainability of PHW-based programs. A unique aspect to our PHW program was the use of a mobile phone intervention as a simple support strategy. The mobile phones allowed us to use local technology to improve communications between PHWs and higher-level providers in a rural setting with poor transport infrastructure. Mobile phone coverage has rapidly expanded in Africa and other RLSs over the past several years, providing opportunities such as this one to creatively use this tool to improve health care by optimizing the way care is organized and delivered.4–6 Addressing the HRHA limitations will require a multifaceted and sustained approach. A valuable and vital component to this approach involves people living with HIV themselves. Interventions utilizing PHWs and mobile phone technology may offer one practical strategy for expanding and improving HIV care in environments with limited health workers and infrastructure.

Use of a Pandemic Preparedness Drill to Increase Rates of Influenza Vaccination Among Healthcare Workers

To determine the effect of a pandemic influenza preparedness drill on the rate of influenza vaccination among healthcare workers (HCWs). Before-after intervention trial. The University of Iowa Hospitals and Clinics (UIHC), a large, academic medical center, during 2005. Staff members at UIHC. UIHC conducted a pandemic influenza preparedness drill that included a goal of vaccinating a large number of HCWs in 6 days without disrupting patient care. Peer vaccination and mobile vaccination teams were used to vaccinate HCWs, educational tools were distributed to encourage HCWs to be vaccinated, and resources were allocated on the basis of daily vaccination reports. Logit models were used to compare vaccination rates achieved during the 2005 vaccination drill with the vaccination rates achieved during the 2003 vaccination campaign. UIHC vaccinated 54% of HCWs (2,934 of 5,467) who provided direct patient care in 6 days. In 2 additional weeks, this rate increased to 66% (3,625 of 5,467). Overall, 66% of resident physicians (311 of 470) and 63% of nursing staff (1,429 of 2,255) were vaccinated. Vaccination rates in 2005 were significantly higher than the hospitalwide rate of 41% (5,741 of 14,086) in 2003. UIHC dramatically increased the influenza vaccination rate among HCWs by conducting a pandemic influenza preparedness drill. Additionally, the drill allowed us to conduct a bioemergency drill in a realistic scenario, use innovative methods for vaccine delivery, and secure administrative support for future influenza vaccination campaigns. Our study demonstrates how a drill can be used to improve vaccination rates significantly.

Scavenger - Mobile Remote Execution

&lt;p&gt;This report describes the design and implementation of a mobile, peerto- peer, remote execution system called Scavenger. A peer running Scavenger is capable of automatically discovering available, unused computing resources in its vicinity, and, by means of mobile code, utilising these resources to its own good.&lt;br /&gt;Designing a system such as Scavenger a number of challenges are raised. In this report only the two main challenges are presented: service discovery and mobile code security.&lt;br /&gt;Service discovery in a fixed network is a well-documented process, but mobile service discovery is less so. Scavenger assumes nothing about its operating environment—it may be executing services on stationary as well as mobile peers—and it therefore needs a highly flexible service discovery protocol.&lt;/p&gt;&lt;p&gt;When working with mobile code, security becomes paramount since peers are executing unknown (and thus untrusted) code. Scavenger uses the Python programming language for its mobile code, and Python does not, like for example Java, have any built-in security models that enable the user to sandbox a Python process. When using such an ”insecure” programming language in a mobile code setting, other means of securing the code must be employed. This report describes the development of such a safe execution environment where mobile Python may be executed in a secure manner.&lt;/p&gt;

‘People Make Assumptions About Our Communities’: Sexual Health Amongst Teenagers from Black and Minority Ethnic Backgrounds in East London

Objectives . (1) To explore sexual behaviour and relationships amongst Black and minority ethnic (BME) teenagers in East London. (2) To examine how these relationships are shaped by culture, gender, peer norms and religion. (3) To describe the implications for sexual health policy and practice in urban, multicultural areas. Design . This report draws primarily on the qualitative arm of a mixed methods study which collected data from 126 young people, aged 15–18, largely through focus groups in the London boroughs of Hackney, Newham and Tower Hamlets. Results . Previous research has reported culture influencing the patterning of risk/protection amongst BME groups. Our data suggest that this is mediated by gender, religion and youth. Religion reportedly influenced young women's sexual behaviour in multiple ways. Young people described gendered norms in meeting and flirting with partners, and the role of mobile phones and peer pressure. Conclusion . Our paper suggests culture, gender, religion and youth influence BME teenagers in aspects of sexual relationships, and that these social markers may have different contextual meanings for individuals. The multiplicity of factors affecting attitudes/behaviour requires a range of contraceptive, counselling, screening and sex education services available for all teenagers, although delivery patterns may differ in response to differing needs.

Reflexive tradition

This article is based on a qualitative study of young working–class men who are dedicated hunters and hardcore wolf adversaries. Our aim is to make sense of their attitudes and practices regarding the re–appearance of wolves. They see the wolves as impeding their life projects: being hunters and outdoorsmen. Therefore, we discuss attitude formation in the light of theories of identity, paying special attention to the idea that identity formation is strongly affected by individualization in ‘late modernity’. Norwegian media tend to depict rural ways of life as rooted in traditionalism, implying an antagonism between the modern and the traditional along an urban–rural axis. Yet, even if important choices made by the young men include distinct elements of local tradition, these choices are no less reflexive than those made by more mobile peers. The article argues that the young hunters are simultaneously traditional and modern and that they transgress such artificial antagonisms through their everyday practices.

Intermittent preventive treatment of malaria in pregnancy: a community-based delivery system and its effect on parasitemia, anemia and low birth weight in Uganda

The main objective of the study was to assess the impact of a community-based delivery system of intermittent preventive treatment (IPT) for malaria in pregnancy with sulfadoxine-pyrimethamine (SP) on access, parasitemia, anemia and low birth weight as primary outcome measures. A study was designed to test the community-based delivery system of IPT through traditional birth attendants (TBAs), drug-shop vendors (DSVs), community reproductive health workers (CRHWs) and adolescent peer mobilizers (APMs), and to compare these with IPT at health units in an area of high malaria transmission - Mukono District, Uganda. Two thousand seven hundred and eighty-five pregnant women participated in the study. The majority of the women (92.4%) at the community-based approaches received their first dose of IPT during their second trimester compared to 76.1% at health units (p<0.0001). At both health units and the community-based approaches, IPT increased mean hemoglobin by 6.7% (p<0.0001) for all parities and by 10.2% among primigravidae. IPT reduced the prevalence of severe anemia from 5.7% to 3.1% (p<0.04). The prevalence of parasitemia was reduced from 24.5% to 16.1% (p<0.001), and parasite density reduced significantly (p<0.02) after the first dose and remained stable with the second dose. Overall the proportion of low birth weight was 6.3% (8.3% at health units versus 6.0% at the community-based approaches, p<0.03) highlighting the importance of access and adherence to IPT. This intervention was acceptable to 89.6% of the women at the community-based approaches intending to use IPT in the future, while 48.1% of them had recommended it to other women. The community-based approaches increased access and adherence to IPT with an effect on anemia, severe anemia, parasitemia and low birth weight. However the reduced effect of IPT on parasitemia points to drug resistance with SP and this requires further evaluation; research into the identification of other more efficacious drugs for malaria prevention in pregnancy is also required.

Intermittent preventive treatment of malaria in pregnancy: the effect of new delivery approaches on access and compliance rates in Uganda

To assess whether traditional birth attendants, drug-shop vendors, community reproductive health workers and adolescent peer mobilizers can administer intermittent preventive treatment (IPT) with sulfadoxine-pyremethamine to pregnant women, and reach those most at risk of malaria and increase access and compliance to it. The study was designed to assess new approaches of delivering IPT through these groups and compare it with IPT at health units. The primary outcome measures were: the proportion of adolescents and primigravidae accessed; gestational age at recruitment and the proportion of women who completed two doses of sulfadoxine-pyremethamine. Two thousand seven hundred and eighty-five pregnant women (78% of those in the study area) participated. With new approaches, 92.4% of the women received IPT during the second trimester as recommended by the policy, vs. 76.1% at health units, P < 0.0001. Of the women who received two doses of sulfadoxine-pyremethamine, 39.9% were at health units (control) vs. 67.5% through new approaches (P < 0.0001). Women using the new approaches also accessed IPT early: the mean gestational age when receiving the first dose of sulfadoxine-pyremethamine was 21.0 weeks vs. 23.1 weeks at health units (P < 0.0001). However, the health units were used by a higher proportion of primigravidae (23.6% vs. 20.0%, P < 0.04), and this was also the case for adolescents (28.4% vs. 25.0%, P < 0.03). This intervention was acceptable with 89.1% of the women at the new approaches intending to use IPT in future. The new approaches increased access to and compliance with IPT. We recommend a review of the policy to allow the provision of IPT through the new approaches.

Dispersed information diffusion with level and schema-based coordination in mobile peer to peer networks

Several open ended issues for high resource availability in mobile peer to peer networks have been examined in the recent past. Different approaches were conducted for supporting information distribution and availability, through guided or unguided packet diffusion. The majority of the recently proposed approaches try to benefit from the spatial characteristics of the dynamically varying topologies. In this work a directed information diffusion scheme is examined using a level and schema-based coordination, applied in mobile peer to peer networks. The prioritization degree of any requested advert is modeled and enables directed prioritized diffusions to end mobile users that are traversing a certain geographic region (location based advertisements). The proposed method is robust in disseminating redundant messages to users while maintaining connectivity through Gradual Energy Tree-based (GET) configuration. Simulation is performed for the examination and performance evaluation of the proposed scheme, taking into account the modeled prioritization as well as the diffusion accuracy by using the Hierarchical and Non-hierarchical GET configuration.

Determinants of Changes in Mobility and Travel Patterns in Developing Countries

This study analyzes changes in sociodemographic, activity, land use, and mobility patterns and their effects on travel dimensions in the context of a developing country. More specifically, increase in vehicle ownership (both two-wheelers and cars) and changes in mode choice over time are observed and analyzed with the use of household data from Chennai, India. Three sources of dynamics are analyzed: exogenous variable dynamics, sensitivity changes over time, and the influence of lagged and persistent effects. The key drivers of growth in travel demand include the increase in vehicle ownership, the number of workers, and the increase in female drivers. The influence of social and technological factors on vehicle ownership and mode choice such as peer pressure and mobile phone ownership are also significant. In addition, the effect of land use, accessibility, and activity has been investigated. Results show significant evidence of differences in travel decisions across different user segments (on the basis of driving knowledge and vehicle–worker ratio) and over time. The proposed disaggregate models provide a reasonably good description (goodness of fit is 47% to 64%) of the observed changes in travel patterns. The findings and results assume importance in the context of increasing congestion, declining public transportation share, and the imminent need for enhancing urban transportation system capacity in cities of developing countries.