We propose a formal model for non-interactive message authentication protocols (NIMAPs) using two channels and analyze all the attacks that can occur in this model. Further, we introduce the notion of hybrid-collision resistant (HCR) hash functions. This leads to a new proposal for a NIMAP based on HCR hash functions. This protocol is as efficient as the best previous NIMAP while having a very simple structure and not requiring any long strings to be authenticated ahead of time. We investigate interactive message authentication protocols (IMAPs) and propose a new IMAP, based on the existence of interactive-collision resistant (ICR) hash functions, a new notion of hash function security. The efficient and easy-to-use structure of our IMAP makes it very practical in real world ad hoc network scenarios. We also look at message recognition protocols (MRPs) and prove that there is a one-to-one correspondence between non-interactive MRPs and digital signature schemes with message recovery. Further, we look at an existing recognition protocol and point out its inability to recover in case of a specific adversarial disruption. We improve this protocol by suggesting a variant which is equipped with a resynchronization process. Moreover, another variant of the protocol is proposed which self-recovers in case of an intrusion. Finally, we propose a new design for message recognition in ad hoc networks which does not make use of hash chains. This new design uses random passwords that are being refreshed in each session, as opposed to precomputed elements of a hash chain.

Vehicular Ad-hoc Networks (VANETs) have emerged as a new application scenario that is envisioned to revolutionize the human driving experiences, optimize traffic flow control systems, etc. Addressing security and privacy issues as the prerequisite of VANETs' development must be emphasized. To avoid any possible malicious attack and resource abuse, employing a digital signature scheme is widely recognized as the most effective approach for VANETs to achieve authentication, integrity, and validity. However, when the number of signatures received by a vehicle becomes large, a scalability problem emerges immediately, where a vehicle could be difficult to sequentially verify each received signature within 100-300 ms interval in accordance with the current Dedicated Short Range Communications (DSRC) protocol. In addition, there are still some unsolved attacks in VANETs such as Denial of Service (Dos) attacks, which are not well addressed and waiting for us to solve. In this thesis, we propose the following solutions to address the above mentioned security related issues. First of all, to address the scalability issues, we introduce a novel roadside unit (RSU) aided message authentication scheme, named RAISE, which makes RSUs responsible for verifying the authenticity of messages sent from vehicles and for notifying the results back to vehicles. In addition, RAISE adopts the k-anonymity property for preserving user privacy, where a message cannot be associated with a common vehicle. Secondly, we further consider the situation that RSUs may not cover all the busy streets of a city or a highway in some situations, for example, at the beginning of a VANETs' deployment period, or due to the physical damage of some RSUs, or simply for economic considerations. Under these circumstances, we further propose an efficient identity-based batch signature verification scheme for vehicular communications. The proposed scheme can make vehicles verify a batch of signatures once instead of one after another, and thus it efficiently increases vehicles' message verification speed. In addition, our scheme achieves conditional privacy: a distinct pseudo identity is generated along with each message, and a trust authority can trace a vehicle's real identity from its pseudo identity. In order to find invalid signatures in a batch of signatures, we adopt group testing technique which can find invalid signatures efficiently. Lastly, we identify a DoS attack, called signature jamming attack (SJA), which could easily happen and possibly cause a profound vicious impact on the normal operations of a VANET, yet has not been well addressed in the literature. The SJA can be simply launched at an attacker by flooding a significant number of messages with invalid signatures that jam the surrounding vehicles and prevent them from timely verifying regular and legitimate messages. To countermeasure the SJA, we introduces a hash-based puzzle scheme, which serves as a light-weight filter for excluding likely false signatures before they go through relatively lengthy signature verification process. To further minimize the vicious effect of SJA, we introduce a hash recommendation mechanism, which enables vehicles to share their information so as to more efficiently thwart the SJA. For each research solution, detailed analysis in terms of computational time, and transmission overhead, privacy preservation are performed to validate the efficiency and effectiveness of the proposed schemes.

Enterprises can adopt branding extension strategies to decrease the expense on developing the awareness of new products as well as to attract consumers. However, not all of them succeeded. From previous researches, most of them focus on brand extensions of tangible products and regard Fit as the main driver to the success of brand extensions. Overall, the higher the Fit between parent brands and extension products, the more possibly brand extensions succeed. However, if Goal Congruency can be a substitute factor for Fit between them, maybe the different goals they possess offer more value to Consumers. Thus, I extend the scope of brand extensions to service industry, studying on the effect of ¡§goal congruency¡¨ on brand extensions and further on the interaction of ¡§goal congruency¡¨ and ¡§advertisement framing¡¨. This research uses situation experiment to manipulate well-known brand to extend new service products. In experiment 1, the real enterprises Friday restaurant and 104 job bank separately launch new extended products to study the effects of ¡§goal congruency" on ¡§perceived value¡¨,¡¨ brand extension attitude¡¨ and ¡§consumers¡¦ mood¡¨. In experiment 2, it adds one more factor, advertisement framing, to study the two- way interaction of consumers¡¦ mood influenced by ¡§goal congruence¡¨ and ¡§advertisement framing¡¨ on ¡§brand extension attitude¡¨. First, it shows the incongruent brand extensions are perceived higher brand extension evaluation than congruent ones. Second, when compared with negative advertisement framing, positive advertisement framing with incongruent brand extensions receives higher brand extension evaluation. The consuming goal can be an important factor on evaluation of brand extensions.

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In the VANET environment, the security of traffic information between vehicles is very important. The messages need to be real-time, and the complexity of authentication should be low. Our proposed method focus on the identity verification based on bilinear pairing, therefore, vehicles, roadside units (RSUs), central authorities (CAs) and trust authority (TA) can verify the identity of each other. After the identity authentication, RSUs will broadcast messages containing chameleon hashing values of verified vehicles, to the other RSUs and vehicles. In the future, vehicles can communicate with the verified vehicles, and verify the messages by these chameleon hashing values. The advantages of the propose method is mainly: 1. Based on the identity-based cryptography (i.e. IBC), the vehicles, RSUs, CAs and TA can verify the message each other. 2. The vehicles can verify the source and legitimacy of the public/private key. 3. The vehicles do not need to show any certificate to verify the identity, avoiding the certificate is exposed for a long time and causing attacks. 4. We can verify the messages through chameleon function and does not need to wait for RSU to verify, it would have good latency performance. 5. We don¡¦t need to re-verify the identity and consult the common keys when the vehicles hand off within the different cover ranges of the RSUs. 6. Not only within the RSUs, our proposal but also can execute in somewhere without RSU. Finally, our proposal method can fulfill the authentication, data integrity, non-repudiation, condition-privacy and untraceable.

This dissertation explores the socio-cognitive system of collective influences on consumers’ evaluation and decision processes, which have not been discussed fully in consumer literature, by examining how people resolve a conflict between group orientation and trait regulatory focus. It is proposed that, depending on the interaction between group commitment and collective efficacy, consumers implement one of three conflict resolution processes (i.e., depersonalization, compliance, and self-preservation) to determine the outcome of their regulatory shift. The impact of these three conflict resolution processes on regulatory shift and following message evaluations are tested with a series of six experiments. The results of these studies showed that people shift their regulatory orientation from trait regulatory focus to group orientation if the group identity is strong enough (experiment 1 and 2), the impact of group orientation on message evaluation is stronger when group members have higher group commitment (i.e., depersonalization; experiment 3 and 4) or experience higher collective efficacy (i.e., compliance; experiment 5), and people experience regulatory non-fit when they follow compliance process and generated less favorable message evaluations than when they follow depersonalization process (experiment 6). These findings highlight the importance of understanding group influence on a consumer’s mindset that consequently affects his/her various psychological processes and consumption behaviors.

With great growth of the use of internet ,the communication based on computer-mediated system or so called electronic word-of-mouth becomes more important. In these ways to exchange information, forward mail is unique and powerful especially. In this research, we would like to know what factors make people to decide to forward a e-mail or not, and what kind of roles these factors play in the process to make decision. Three factors were discussed in this research, including¡Gmessage framing, source credibility and product involvement, and the theory of reasoned action was applied to explain the behavior of forwarding e-mail. Through ANOVA and regression analysis to analyze 472 effective samples, the findings are outlined below¡G 1. E-mail users hold better attitude to forward negative message, and have more intention to forward it. 2. E-mail users hold better attitude to forward the message which has high source credibility, and have more intention to forward it. 3. The effect of subjective norm on intention to forward the email is greater than the effect of attitude.

Abstract This study explores the feasibility of applying mobile phone¡¦s value-added services in attracting adolenscents¡¦ participation in local festival. In recent years, Taiwan¡¦s local governments have been considering how to effectively enhance cultural identities and promote cultural tourism through conducting various kinds of festivals. Against this backdrop, the introduction of using mobile phone for festival marketing is seriously considered. Although adolescents are the group most in need of cultivation of local culture, previous marketing effort proved to be fruitless. Traditional festivals continue attracting visitors from the so-called cultural tourists ¡V those already with cultural knowledge of the tourist site (known as tourist gaze). Usually it was in the ccasion of family tour that adolescents would participate in festivals. Therefore, it has been an issue regarding how to attract adolescents in attending festivals. While adolescents are characterised by the nature of social grouping, plus high flexibility of adopting new technologies, the auther is most interested in how to use mobile phones as a effective means for attracting them to festival places. By conducting a survey of 738 valid samples, generally aged 14-16, from Kaohsiung¡¦s public high schools, the author uses factor analysis to sort out perceiveably the most favorable marketing tools. Short message service (SMS) stands out as the first choice. They also favour value-added services that adds with local culture taste. Particularly they would welcome value-added services that can incorporate role models, favourite products, and group activities into festival marketing. Using adolescents¡¦ familiar jargons will touch their heart as well. This study would contribute to the understanding of Kaohsiung¡¦s adolescents in adopting and using information and communications technologies (ICTs) in general, and whether they would accept mobile marketing for promoting festivals in particular. Hopefully by using this findings as an clue or a guide, local governments and telecommunications operators can design a better-planned and effective festival marketing arrangement which can further help constructs adolescents¡¦ local cultural identity. Keywords: mobile phone, value-added services, festival, marketing, short message, service (SMS)

Abstract Wireless communication and monitoring have been applied in military and other related engineering for couples of year. The application concept of this technology is now initiating in family life and the power monitoring of home scale combined with network and wireless communication will be setup in this study. This thesis is based on the use of PIC 16F877 microprocessor as main unit to catch the equipment information and treat the process of state control. The interchange control between information and main computer will be employed by RF wireless modulus. The drawing-type interface of human/machine is designed by using the software of Labview. The internet obeying agreements of TCP/IP communication combined with global movable communication of GSM will be built up to carry out the wireless remote control for safety-management system of power equipment by fast information transfer. This system was approved to meet the define requirements through the processes of analysis¡Bdesign¡Bmanufacturing and test.

The debate about how to frame health messages to maximize their effectiveness is ongoing. Research supports the use of both positive and negative frames under different conditions. This project was developed to further clarify the circumstances under which a negative frame may be harmful, or even backfire. In Study 1 it was proposed that past drinking behavior would moderate the relationship between message frame and behavioral intention to drink alcohol in the future such that people with a heavy drinking past would react to a negatively framed message by increasing their intention to consume alcohol. A total of 212 students participated in the study where they completed a questionnaire to provide information on some of the key variables, such as drinking history, and then were asked to read mock health materials with either a positive or negative frame. They concluded the study by responding to a final questionnaire where they provided feedback on the health materials and indicated their intentions to drink in the future. Results of this study supported the hypothesis. The goals of Study 2 were to replicate the findings of Study 1 and to test the hypothesis that self-esteem would be a second-order moderator of this effect such that people with a heavy drinking past and high self-esteem would be most likely to respond to a negatively framed message by increasing their intention to drink alcohol in the future. A total of 490 students participated in the study, which followed the same procedure as the first study. Results of Study 2 failed to replicate the findings from Study 1, and indicated that self-esteem did influence the relationship between past behavior, message frame and behavioral intention but not in the proposed direction. The marginally-significant effect found in Study 2 suggested that heavy drinkers with high self-esteem were actually more likely to decrease their intentions to drink alcohol after reading a negatively framed message. Because of the inconsistency in the results of the two studies presented, proposed directions for future research are discussed.