Cross-Layer Theoretical Analysis of NC-aided Cooperative ARQ Protocols in Correlated Shadowed Environments

In this paper, we propose a cross-layer analytical model for the study of network coding (NC)-based Automatic Repeat reQuest (ARQ) medium access control (MAC) protocols in correlated slow-faded (shadowed) environments, where two end nodes are assisted by a cluster of relays to exchange data packets. The goal of our work is threefold: 1) to provide general physical-layer theoretical expressions for estimating crucial network parameters (i.e., network outage probability and expected size of the active relay set), applicable in two-way communications; 2) to demonstrate how these expressions are incorporated into theoretical models of the upper layers (i.e., MAC); and 3) to study the performance of a recently proposed NC-aided cooperative ARQ (NCCARQ) MAC protocol under correlated shadowing conditions. Extensive Monte Carlo experiments have been carried out to validate the efficiency of the developed analytical model and to investigate the realistic performance of NCCARQ. Our results indicate that the number of active relays is independent of the shadowing correlation in the wireless links and reveal intriguing tradeoffs between throughput and energy efficiency, highlighting the importance of cross-layer approaches for the assessment of cooperative MAC protocols

Let it Rock: The Effects of Brand Name Placement in Songs on Attitudes toward the Artist and the Brand

This paper focuses on a specific type of product placement, namely brand placement in song lyrics and particularly on its impact over consumers' attitudes toward the brand and the artist. Three significant factors were identified in the literature and manipulated through two experiments: Congruence of the artist-brand dyad, strength and valence. Whereas the impact of congruence on product placement has been proven (Russell, 2002), the last two elements are novel and explicitly stated as important for future research (Balasubramanian, Karrh and Patwardhan, 2006). Congruence Russell (2002) develops the notion of congruence as a major factor determining audiences' reactions toward product placement. Incongruent information triggers cognitive elaboration and auditors' attention, thus improving the memory of the placement. Whereas congruence enhances realism, incongruent information elicits suspicions about the reasons for the brand appearing in the show; thus triggering unfavourable effects on evaluation. Russell (2002) conceptualizes congruence as the combination of modality (visual / audio) and plot connection (lower / higher). In this research, congruence was conceptualized as the fit or match between the brand and the artist. The first study probes the proposed model in an incongruent artist-brand dyad, and the second study investigates the congruent artist-brand dyad. Valence In general, academic literature suggests that putting forward product advantages rather than disadvantages enhances the attitude toward it, and vice versa when communication for the product is negative (Balasubramanian, 1994). Notwithstanding that several variables are considered to moderate the effects of negative communication on attitudes toward brands (Ahluwalia, Bumkrant, and Unnava, 2000; Till and Shimp, 1998), recent studies proved that, under certain circumstances, negative communication related to products can yield positive cues (Money, Shimp and Sakano, 2006). In addition, in line with Campbell's (1995) attention-getting tactics research, placing positive brand arguments in songs may be perceived as manipulated communication by audiences. Building on the previous arguments, the hypotheses laid out in this paper suggest that individuals will have more positive attitudes toward artists and brands when the communication valence is negative, compared to less favourable attitudes when the communication valence is positive. Strength The influence of the communication modality will be moderated by the strength of the relationship between the artist and the brand. In the context of product placement in movies or sitcoms, strength is operationalized by fore versus background placement or by visual only versus visual and verbal placements (Russell and Stern, 2006). As this study concerns music songs, strength was implemented by repeating a brand name as to reinforce the association with the artist. Balasubramanian et al. (2006) specifically underlined the importance of "repetition" as an operationalization mode that could have a significant influence on product placement effectiveness. Therefore, the effect of repetition is seen as a catalyser of communication on attitudes, and depends on whether the product is communicated positively or negatively. Studies Two scenario based studies (coherent/incoherent brand-artist dyad) were designed and implemented to test the hypotheses. Eight scenarios were crafted (four scenarios per study); each of them combined the effect of communication valence (positive/negative) and strength (repeated/not repeated). One artist was chosen and remained constant across all eight scenarios. Two brands were chosen to create an incoherent artist-brand dyad (used in study one) and a coherent artist-brand dyad (used in study two). These were chosen while executing several pretests after which the appropriate stimuli were obtained. To avoid likeability, an equally liked / disliked artist and two neutrally liked brands were selected. The studies were carried-out among a sample of undergraduate students. These were given two booklets presented as unrelated studies belonging to two different researchers. The first booklet was presented as a study on general attitudes concerning celebrities and brands; the second booklet was presented as a study on new trends in the music industry. Respondents were asked to imagine a situation in which they were invited by a music company to listen to new songs from a given artist, in order to assess the new album. It was stipulated in each scenario that the artist mentioned in his lyrics (either in a positive or negative valence) once only or several times (strength) a brand (either incongruent in study one or congruent in study two). Finally, respondents were asked about their attitudes toward the artist and the brand using a five item 7 point Likert scale (Aggarwal, 2004). Several manipulation checks were executed to ascertain the reliability of the manipulations. Two (incongruent/congruent) 2 X 2 (valence: positive vs. negative; strength: none repeated vs. repeated) between-participant ANCOVAs were performed to measure the effect of treatments over attitudes toward the artist and the brand. The most significant results are: Incongruent artist-brand dyad-attitudes toward the artist: The two-way interaction between valence and strength was significant. A planned contrast revealed that if a brand is communicated negatively and for repeated times, the average attitude toward the artist is more positive compared to the attitude when the brand was communicated positively and for repeated times. In contrast, when a brand is communicated negatively but not repeatedly, no significant difference was reported compared to a brand communicated positively but not repeatedly. Incongruent artist-brand dyad-attitudes toward the brand: The between-participant effect of valence was significant. Participants reported more favorable attitudes toward the brand after the artist mentioned the brand negatively instead of positively. However, the two-way interaction between valence and strength was non significant. Congruent artist-brand dyad-attitudes toward the artist: The between-participant effect of valence was significant. Participants reported more favorable attitudes toward the artist after he mentioned the brand negatively instead of positively. However,770 / Let it Rock: The Effects of Brand Name Placement in Songs on Attitudes toward the Artist and the Brand the two-way interaction between valence and strength was non significant. Congruent artist-brand dyad-attitudes toward the brand: The two-way interaction between valence and strength was significant. A planned contrast revealed that if a brand is communicated negatively and for repeated times, respondents have more positive attitudes toward the brand compared to attitudes when it is communicated positively and for repeated times. No significant difference was observed over the attitude toward the brand when this was not repeated, irrespective of the positive or negative communication modality. Implications for marketers are considerable, since misused valence can discount individuals' attitudes over brands and artists. Finally, the research proposed several findings which could be worth considering in better law framing, due to the ethical implications that hybrid messages contain

Product Placement in Song Lyrics: Impact of Cognitive Load, Disclosure, Valence and Strength

Through three studies, we investigate consumer attitudes and memory toward artists and brands engaging in product placement in song lyrics. The first study demonstrates that attitudes toward the artist, but not toward the brand, are less positive when respondents are made aware about a commercial deal between the artist and the brand. The second study replicates and extends the first one, notably through the inclusion of cognitive busyness and memory. The third study assesses the impact of the placement’s valence and strength. Results show that when a brand is repeated positively, attitudes toward the artist and the brand decline