Low density parity check codes: a statistical physics perspective

The modem digital communication systems are made transmission reliable by employing error correction technique for the redundancies. Codes in the low-density parity-check work along the principles of Hamming code, and the parity-check matrix is very sparse, and multiple errors can be corrected. The sparseness of the matrix allows for the decoding process to be carried out by probability propagation methods similar to those employed in Turbo codes. The relation between spin systems in statistical physics and digital error correcting codes is based on the existence of a simple isomorphism between the additive Boolean group and the multiplicative binary group. Shannon proved general results on the natural limits of compression and error-correction by setting up the framework known as information theory. Error-correction codes are based on mapping the original space of words onto a higher dimensional space in such a way that the typical distance between encoded words increases.

An exploratory study of management accounting and control systems in a developing country

This thesis reports on the results of case studies in four commercial banks in Nigeria. The study focuses how management accounting and control systems (MCS) operate in the four banks. The study is motivated by the dearth of literature on management accounting practices in the developing world in general and in Nigeria in specific. The case study approach adopted in conducting the research was useful in exploring the dynamics of the MCS in the organisations. Data was gathered from two sources. First, semi-structured interviews were conducted with managers at the head office, regional office and branches of each bank. The participants were selected from different backgrounds and managerial levels to provide broader understanding of the operations of the MCS. Second, various internal and external documents were reviewed to provide supporting evidence for the interview results. New institutional sociology (NIS) provided the theoretical framework to understand the results. NIS provided explanations for how the MCS in the four banks were shaped by diverse external and internal factors. The key factors identified as shaping the operations of the MCS were the need to comply with the regulatory environment (coercive isomorphism), the need to maintain social and cultural support (normative isomorphism) and the need to imitate successful organisations in order to appear legitimate (mimetic isomorphism). The study also examines the interplay between the institutional forces, market forces and infra-organisational power relations. This analysis is necessary to overcome the criticism of NIS that it downplays the role of market forces, agency and intra-organisational relations. The findings of the study have implications for understanding the operations of MCS in the developing world.

Corporate governance and compliance with International Financial Reporting Standards (IFRSs):evidence from two MENA stock exchanges

This study examines the influence of corporate governance structures on the levels of compliance with IFRSs disclosure requirements by companies listed on the stock exchanges of two leading MENA (Middle East and North Africa) countries, Egypt and Jordan. This study employs a cross-sectional analysis of a sample of non-financial companies listed on the two stock exchanges for the fiscal year 2007. Using an unweighted disclosure index, the study measures the levels of compliance by companies listed on the two stock exchanges investigated.Univariate and multivariate regression analyses are used to estimate the relationships proposed in the hypotheses. In addition, the study uses semi-structured interviews in order to supplement the interpretation of the findings of the quantitative analyses. An innovative theoretical foundation is deployed, in which compliance is interpretable through three lenses - institutional isomorphism theory, secrecy versus transparency (one of Gray’s accounting sub-cultural values), and financial economics theories. The study extends the financial reporting literature, cross-national comparative financial disclosure literature, and the emerging markets disclosure literature by carrying out one of the first comparative studies of the above mentioned stock exchanges. Results provide evidence of a lack of de facto compliance (i.e., actual compliance) with IFRSs disclosure requirements in the scrutinised MENA countries. The impact of corporate governance mechanisms for best practice on enhancing the extent of compliance with mandatory IFRSs is absent in the stock exchanges in question. The limited impact of corporate governance best practice is mainly attributed to the novelty of corporate governance in the region, a finding which lends support to the applicability of the proposed theoretical foundation to the MENA context. Finally, the study provides recommendations for improving de facto compliance with IFRSs disclosure requirements and corporate governance best practice in the MENA region and suggests areas for future research.