Link Quality Control Mechanism for Selective and Opportunistic AF Relaying in Cooperative ARQs: A MLSD Perspective

Incorporating relaying techniques into Automatic Repeat reQuest (ARQ) mechanisms gives a general impression of diversity and throughput enhancements. Allowing overhearing among multiple relays is also a known approach to increase the number of participating relays in ARQs. However, when opportunistic amplify-and-forward (AF) relaying is applied to cooperative ARQs, the system design becomes nontrivial and even involved. Based on outage analysis, the spatial and temporal diversities are first found sensitive to the received signal qualities of relays, and a link quality control mechanism is then developed to prescreen candidate relays in order to explore the diversity of cooperative ARQs with a selective and opportunistic AF (SOAF) relaying method. According to the analysis, the temporal and spatial diversities can be fully exploited if proper thresholds are set for each hop along the relaying routes. The SOAF relaying method is further examined from a packet delivery viewpoint. By the principle of the maximum likelihood sequence detection (MLSD), sufficient conditions on the link quality are established for the proposed SOAF-relaying-based ARQ scheme to attain its potential diversity order in the packet error rates (PERs) of MLSD. The conditions depend on the minimum codeword distance and the average signal-to-noise ratio (SNR). Furthermore, from a heuristic viewpoint, we also develop a threshold searching algorithm for the proposed SOAF relaying and link quality method to exploit both the diversity and the SNR gains in PER. The effectiveness of the proposed thresholding mechanism is verified via simulations with trellis codes.Comment: This paper has been withdrawn by the authors due to an improper proof for Theorem 2. To avoid a misleading understanding, we thus decide to withdraw this pape

Climate Warming’s Alteration of Host-Parasite Dynamics

Parasites and pathogens have significant roles in host population control, and thus host-parasite interactions affect biodiversity. The important question reviewed in this paper is how changes in temperature due to climate change affect host-parasite interactions. There is mounting evidence that elevated temperatures have both beneficial and detrimental effects on parasites and independently on hosts. These independent changes result in altered host-parasite dynamics through various mechanisms. If elevated temperatures enhance parasite survival, risk of disease transmission among hosts is enhanced as well. This enhancement is dependent on temperature-induced shifts in the host lifecycle, as asynchrony in host and parasite development can result in decreased infection rate and disrupted disease transmission regardless of the increase in parasite survival and density. Host species differ in their responses to temperature elevation. Increased temperature can alter their susceptibility to parasites through changes in their immune functions. Climate shifts also result in host range shifts. As host ranges expand, they may encounter novel pathogens, increasing the risk of spillovers and resulting in a greater mortality rate. From the point of view of native species, newly arriving host species present the potential danger of introducing novel parasites and diseases, which can be detrimental to native species. For seasonally migratory species whose parasites typically decrease during their absence, any climate-induced increase in their parasites’ survival prior to their return may decrease the effectiveness of migration, shift their lifestyle to become more sedentary and thus reshape host-parasite dynamic. Altered balance of host-parasite interactions produces changes at higher ecological levels, and the efforts to conserve parasites should thus have the same priority as the need to conserve host species

Exploring the Association between Network, Cognitive, Structural Social Capital and the Risk of Clinical Depression in Taiwan

Depression is the one of most common mental health conditions in Taiwan. Although evidence suggests that social capital is associated with depression, few studies have comprehensively explored the influence of social capital on depression. Also evidence in Taiwan is limited in comparison to other Western countries. Data from the 1997 Taiwan Social Change Survey (n=2,598), which is the only dataset that contains the best available information to measure and compare all three dimensions of social capital (network, cognitive, and structural social capital), were used to examine the association between three dimensions of neighborhood- and individual-level social capital and depression among Taiwanese adults 20 years and older. The 20-item Center for Epidemiological Studies Depression Scale was used to measure depressive symptoms; scores ≥ 15 indicated being at a risk for clinical depression. Three dimensions of social capital were assessed: cognitive social capital (measured using questions on perceived neighborhood trust and reciprocity), structural social capital (measured using questions about local social participation), and network social capital (measured using a position generator). In order to develop a greater understanding of the mechanisms linking social capital and depression, multivariable logistic regression models were used to assess the relationship between the three dimensions of social capital and the risk of clinical depression, the association between age-based patterns of social capital and the risk of clinical depression, and the independent association between neighborhood-level social capital and the risk of clinical depression. The main findings from this study suggest the dimensions of social capital did not have the same relationship with being at the risk of clinical depression. Higher scores of cognitive social capital and structural social capital were both independently associated with lower odds of being at risk for clinical depression after controlling for potential confounders. Network social capital was not associated with being at risk for clinical depression except for network diversity. In the second paper, the study revealed that there are different age patterns for network, cognitive and structural social capita but we only observed age variations in network social capital and the risk for clinical depression among age 65 and older. The results from the third paper showed that neighborhood-level social capital was not associated with the risk of clinical depression. Disentangling the multidimensional and multilevel nature of social capital may inform our understanding of the mechanisms linking social capital and depression to promote mental health

Brand and public relations in the Taiwanese not-for-profit sector : a case study of the Eden Social Welfare Foundation

In a competitive environment in Taiwan, not-for-profit organisations (NPOs) seek to differentiate themselves from other NPOs. ‘Brand’ improves the internal functions and competitiveness of these NPOs; attracts funding to them by making use of public relations (PR) strategies and techniques and expanding the access to public resources; and also conveys a slick corporate image to the public. This research project has adopted a PR perception of leading marketing concepts to look at charity brand strategy. This approach has been taken instead of the more common marketing-oriented perspective. NPOs exist because of their public service or social welfare missions. The best way to increase income is to raise accountability and interactions with the public or corporations through ethical relationship management as part of NPO PR practice. This thesis takes as its subject the Eden Social Welfare Foundation, which was established in 1985 and is one of Taiwan’s top five NPOs. The challenges faced by Eden in presenting itself as a caring, non-partisan organisation in an age of branding, competition and a public sensitive to the ethos of charity is investigated. The purpose of this study is to: (1) explore the role of branding within PR; (2) discuss how media represents NPOs to their stakeholders; (3) investigate co-branding issues in cooperative relationships involving differential power relations; (4) investigate the ethical risk of mission drift, where NPOs charged with a public mission can lose their way by becoming corporatised. In a comprehensive overview of the complexity of NPO PR, branding and power relations in Taiwan, relationship management has been shown to be at the heart of NPO PR. Trust is the critical element that ensures the organisation stays on the right path. This research has found, on one hand, that higher brand value facilitates better communication and involves shifts of power through brand power, media access, social networking and know-how. Co-branding and media coverage are assistant contributors, through framing, in building the charity brand. On the other hand, the study suggests ways to rethink the negotiation of power relations and the social perspectives between the public interest and commerce. Consideration should be given to a monitoring system for NPOs to ensure accountability and visibility that guarantees the public interest. The results also suggest that investment in training and upgrading skills in communication with outsiders is important in Taiwan, as part of NPO PR practice