<p>The purpose of this thesis work was to make a survey of current on-line payment technologies and find out which are they and how do they work? Compare and analyze them from a security point of view, as well as a usability point of view. What is good? What is bad? What is lacking?</p><p>To achieve this purpose, an overview of the current on-line payment technologies was acquired through academic books and papers, Internet sites, magazines. Basic cryptographic and security related techniques were studied for the security analysis of current on-line payment systems.</p><p>In this work, various current on-line payment systems were classified into two groups [Macro and Micro on-line payment systems]. This classification was based on the mode of on-line payment transactions. To analyze these on-line payment systems, a set of payment system requirements were formed [Security Issues, Usability Issues, Anonymity, Scalability etc].</p><p>Under the category of Macro payment system, Credit Card payment system, Debit Card payment system, Stored Value Card payment system, Electronic Check payment system, Electronic Cash payment system, Electronic account transfer payment system and mobile payment system transactions were examined.</p><p>Under the category of Micro payment system, Hash Chain based Payment System, Hash Collisions and Hash sequences based Payment Systems, Shared Secrete Keys based Payment Systems and Probability based payment systems were examined.</p><p>Based on the requirements of payment system, these on-line payment systems were analyzed and compared. In the analysis phase, the advantages and drawbacks of these payment systems were figured out.</p><p>It was found from the study that the credit card based payment systems are the most widely used means of conducting on-line payments. It is evident that credit card based payment systems satisfy stakeholder requirements the best, as they offer more flexible payment options, having a large user-base, benefit from familiarity and simplicity of use and also allow international payments. The other on-line payment systems lack this flexibility</p><p>It can also be extracted from the study that users want more simplified, convenient and secure on-line payment systems. Thus the futuristic on-line payment systems will have all secure payment options into one system.</p>

The study describes 52 patients' experiences and feelings towards theirillness and the care received in connection with it. The main purpose ofthe study is to gather knowledge on cancer patients' need of psychosocialcare and from this insight draw up a proposition for a clinically usefulmethod for psychosocial care. I have met and spoken with the patients,each suffering from a different form of cancer, on one occasion. They areall patients o'f the Department of General Surgery, Östersund Hospital.The taped conversations constitute the most important source for thisthesis, which has its crucial point in the empirical part. My theoreticalframe of reference has a psychodynamic and existential perspective.To distinguish and give as clear a picture as possible on "what it'slike to get a cancer and live with it", different phases have been drawnup showing the process of a cancer. Living with a cancer means adjustingto constant uncertainty and a fear of recurrence. That which is typicalfor the process of a cancer is that a crisis here is so different fromthe "classical" pattern of reaction and comes and goes in waves.The different phases show unsatisfactory psychosocial care and the mostobvious déficiences are to be found in connection with the first consultationwith a doctor, when receiving the diagnosis and also at the routinecheck-ups.That which, like the symbolic main thread, runs through the whole dissertationis the lack of dialogue and criticism of the inferior continuityamong the doctors.In the last chapter I have made a suggestion for the future psychosocialcare of cancer patients. / digitalisering@umu

This thesis investigates channel-coded physical layer network coding, in which the relay directly transforms the noisy superimposed channel-coded packets received from the two end nodes, to the network-coded combination of the source packets. This is in contrast to the traditional multiple-access problem, in which the goal is to obtain each message explicitly at the relay. Here, the end nodes $A$ and $B$ choose their symbols, $S_A$ and $S_B$, from a small non-binary field, $\mathbb{F}$, and use non-binary PSK constellation mapper during the transmission phase. The relay then directly decodes the network-coded combination ${aS_A+bS_B}$ over $\mathbb{F}$ from the noisy superimposed channel-coded packets received from two end nodes. Trying to obtain $S_A$ and $S_B$ explicitly at the relay is overly ambitious when the relay only needs $aS_B+bS_B$. For the binary case, the only possible network-coded combination, ${S_A+S_B}$ over the binary field, does not offer the best performance in several channel conditions. The advantage of working over non-binary fields is that it offers the opportunity to decode according to multiple decoding coefficients $(a,b)$. As only one of the network-coded combinations needs to be successfully decoded, a key advantage is then a reduction in error probability by attempting to decode against all choices of decoding coefficients. In this thesis, we compare different constellation mappers and prove that not all of them have distinct performance in terms of frame error rate. Moreover, we derive a lower bound on the frame error rate performance of decoding the network-coded combinations at the relay. Simulation results show that if we adopt concatenated Reed-Solomon and convolutional coding or low density parity check codes at the two end nodes, our non-binary constellations can outperform the binary case significantly in the sense of minimizing the frame error rate and, in particular, the ternary constellation has the best frame error rate performance among all considered cases.

Developments in information technology and tangible computing facilitate the human’s life by inventing Self Service Technologies SSTs where it changed the way we interact with the environment as well as new technologies did. Nowadays, a lot of new technologies have embodied computer inside such as smartphone and computer tablets. Previous studies in adoption of SSTs research treat customer behavior towards technology based services. However, recent studies recognize that participants have different attitude towards different technologies even if these technologies used to support the same service. Therefore, in our thesis we are going to study the effect of smartphone i.e. iPhone and computer tablets i.e. iPad on adoption of three services of SSTs Internet Banking, Online Shopping and Self Check In Machine at Airports. Is there any hesitation while people adopting with this technology? If yes, why does it happen? Our data were collected by conducting a pilot and empirical study via using quantitative and qualitative approaches. We conducted our study at Umeå, Sweden. The study findings present the effect of adoption through age, family, friends, money, knowledge, using technology in public and private places, mobile technology and computer tablets, and Interface design on adoption SSTs. We found that participants were influenced by new technology for adopting SSTs. Participants did not use Online Shopping as much as they use Internet Banking, especially in the private places. Concerning the Self Check in Machines, participants were differential in which some tend to use it and others did not.

Recently, low-density parity-check (LDPC) codes have attracted much attention because of their excellent error correcting performance and highly parallelizable decoding scheme. However, the effective VLSI implementation of and LDPC decoder remains a big challenge and is a crucial issue in determining how well we can exploit the benefits of the LDPC codes in the real applications. In this master thesis report, following a error coding background, we describe Low-Density Parity-Check codes and their decoding algorithm, and also requirements and architectures of LPDC decoder implementations.

The family of Low Density Parity Check (LDPC) codes is a strong candidate to be used as Forward Error Correction (FEC) in future communication systems due to its strong error correction capability. Most LDPC decoders use the Message Passing algorithm for decoding, which is an iterative algorithm that passes messages between its variable nodes and check nodes. It is not until recently that computation power has become strong enough to make Message Passing on LDPC codes feasible. Although locally simple, the LDPC codes are usually large, which increases the required computation power. Earlier work on LDPC codes has been concentrated on the binary Galois Field, GF(2), but it has been shown that codes from higher order fields have better error correction capability. However, the most efficient LDPC decoder, the Belief Propagation Decoder, has a squared complexity increase when moving to higher order Galois Fields. Transmission over a channel with M-PSK signalling is a common technique to increase spectral efficiency. The information is transmitted as the phase angle of the signal. The focus in this Master’s Thesis is on simplifying the Message Passing decoding when having inputs from M-PSK signals transmitted over an AWGN channel. Symbols from higher order Galois Fields were mapped to M-PSK signals, since M-PSK is very bandwidth efficient and the information can be found in the angle of the signal. Several simplifications of the Belief Propagation has been developed and tested. The most promising is the Table Vector Decoder, which is a Message Passing Decoder that uses a table lookup technique for check node operations and vector summation as variable node operations. The table lookup is used to approximate the check node operation in a Belief Propagation decoder. Vector summation is used as an equivalent operation to the variable node operation. Monte Carlo simulations have shown that the Table Vector Decoder can achieve a performance close to the Belief Propagation. The capability of the Table Vector Decoder depends on the number of reconstruction points and the placement of them. The main advantage of the Table Vector Decoder is that its complexity is unaffected by the Galois Field used. Instead, there will be a memory space requirement which depends on the desired number of reconstruction points.

The area of cooperative communications has received tremendous research interest in recent years. This interest is not unwarranted, since cooperative communications promises the ever-so-sought after diversity and multiplexing gains typically associated with multiple-input multiple-output (MIMO) communications, without actually employing multiple antennas. In this dissertation, we consider several cooperative communication channels, and for each one of them, we develop information theoretic coding schemes and derive their corresponding performance limits. We next develop and design practical coding strategies which perform very close to the information theoretic limits. The cooperative communication channels we consider are: (a) The Gaussian relay channel, (b) the quasi-static fading relay channel, (c) cooperative multiple-access channel (MAC), and (d) the cognitive radio channel (CRC). For the Gaussian relay channel, we propose a compress-forward (CF) coding strategy based on Wyner-Ziv coding, and derive the achievable rates specifically with BPSK modulation. The CF strategy is implemented with low-density parity-check (LDPC) and irregular repeataccumulate codes and is found to operate within 0.34 dB of the theoretical limit. For the quasi-static fading relay channel, we assume that no channel state information (CSI) is available at the transmitters and propose a rateless coded protocol which uses rateless coded versions of the CF and the decode-forward (DF) strategy. We implement the protocol with carefully designed Raptor codes and show that the implementation suffers a loss of less than 10 percent from the information theoretical limit. For the MAC, we assume quasi-static fading, and consider cooperation in the low-power regime with the assumption that no CSI is available at the transmitters. We develop cooperation methods based on multiplexed coding in conjunction with rateless codes and find the achievable rates and in particular the minimum energy per bit to achieve a certain outage probability. We then develop practical coding methods using Raptor codes, which performs within 1.1 dB of the performance limit. Finally, we consider a CRC and develop a practical multi-level dirty-paper coding strategy using LDPC codes for channel coding and trellis-coded quantization for source coding. The designed scheme is found to operate within 0.78 dB of the theoretical limit. By developing practical coding strategies for several cooperative communication channels which exhibit performance close to the information theoretic limits, we show that cooperative communications not only provide great benefits in theory, but can possibly promise the same benefits when put into practice. Thus, our work can be considered a useful and necessary step towards the commercial realization of cooperative communications.

Recently, a novel technique for multi-user spread-spectrum mobile systems, the called interleave-division multiple-access (IDMA) scheme, was proposed by L. Ping etc. The advantage of IDMA is that it inherits many special features from code-division multiple-access (CDMA) such as diversity against fading and mitigation of the other-cell user interference. Moreover, it¡¦s capable of employing a very simple chip-by-chip iterative multi-user detection strategy. In this thesis, we investigate the performance of combining IDMA and orthogonal frequency-division multiplexing (OFDM) scheme. In order to improve the bit error rate performance, we applied low-density parity-check (LDPC) coding to the proposed scheme, named by LDPC Coded OFDM-IDMA Systems. Based on the aid of iterative multi-user detection algorithm, the multiple-access interference (MAI) and inter-symbol interference (ISI) could be canceling efficiently. In short, the proposed scheme provides an efficient solution to high-rate multiuser communications over multipath fading channels.

生活於行動網絡與社群網站發展快速的今日，人們逐漸依賴利用隨手可得之行動裝置紀錄生活，打卡儼然成為生命紀錄的方式之一。本研究致力於提供使用者個人化之打卡系統，讓使用者在選用群眾所推薦的地理標籤名稱之餘，同時保有個人化情感傾向特色之地理標籤名稱。透過基於地緣情感關係連結之群眾推薦地理標籤名稱，我們提供更貼近使用者個人情感偏好之地理標籤，讓使用者在省下自行建立個人化地理標籤名稱上的繁瑣程序的同時，還能同時保有個人化特色，更能夠作為未來回憶時之線索。在實驗設計上，我們邀請共二十八位受試者使用本研究所開發之打卡系統，利用三週的時間真實模擬生活中的打卡情況。我們分析受試者進行打卡時所選用的地理標籤名稱來源作為評估之依據，透過實驗結果顯示基於地緣情感關係連結之群眾推薦地理標籤名稱模型，能夠推薦較適合的地理標籤名稱給使用者使用。因此本研究有效利用特定群眾之力量協助使用者建立個人化之地理資訊。 / In the present, people used to have one or more mobile devices. With the mobile devices thriving, the social network is also getting more popular. People rely on the mobile devices or social network to record their lives—“Check in” is becoming a kind of “lifelog”. Our research provides user a customized check in system, which can free users from the troublesome procedures, naming the geotag by their own, meanwhile; they can still have their own style. Furthermore, this customized name of geotag will be the hint to their memory in the future. When it comes to the experiment, we have 28 users experience our check in system, and we spent three weeks to simulate the situation of check in in the real life. We analyze the users’ name of geotag and use it as the result to estimate. According to the result of our experiment, the Location-Based Emotion Connected model can recommend a better name of geotag to the users. Consequently, our research the effective help people to construct personalizes geographic information.

The purpose of this multicase study was to describe and explain the perceptions of three Spanish-English culturally and linguistically diverse (CLD) high achievers on their biliteracy journeys to become educators in the United States (U.S.), by answering: What elements constitute the perspectives of three L1-Spanish/L2-English CLD high achievers on the relevance of their biliteracy experience in order to become educators in the U.S.?; What factors do these three L1-Spanish/L2-English CLD high achievers perceive as key to describe their biliteracy experience?; What relevance, if any, do these three L1-Spanish/L2-English CLD high achievers perceive their biliteracy experience had for them to become educators in the U.S.?; From the perspectives of these three L1-Spanish/L2-English CLD high-achiever educators, what impact, if any, did digital technologies have on their biliteracy experience? With a critical-pedagogy approach to multicase-study (Stake, 2006) inquiry, I used online methods to collect data on three high-achieving (GPA > 3.01) L1-Spanish graduates initially identified as limited-English-proficient by the American school system. For data collection, I used a participant-selection questionnaire, individual and group semi-structured interviews via Skype, e-journals for biliteracy autobiographies, artifact e-portfolios, my reflective e-journal, and one face-to-face unstructured interview with one participant only. Concurrently, I engaged in on-going data analysis to build meaning inductively and guide further data collection, analysis, and interpretation, until saturation, in an application of the dialectical method into research (Ollman, 2008). I included the email communications with the participants and their member checks. Two external auditors reviewed all data-collection and analytic procedures. I analyzed each case individually followed by the cross-case analysis. The findings indicated the importance of family and L1-community support, host-culture insiders as mentors, access to information, empowerment by means of conscientization, and the participants' advocacy of others by becoming educators. In this way, the study identified how the participants escaped the statistics of doom, which helps understand how to better serve growing L2-English student populations. The study closed with a discussion from the viewpoint of reviewed literature and critical pedagogy, my interpretation of the findings, and suggestions for future praxis in education and research.