Theory of Coupled Resonator Optical Waveguides (CROW) Exhibiting High Order Exceptional Points of Degeneracy

We present a novel approach and a theoretical framework for generating high order exceptional points of degeneracy (EPD) in photonic structures based on periodic coupled resonators optical waveguides (CROWs). Such EPDs involve the coalescence of Floquet-Bloch eigenwaves in CROWs, without the presence of gain and loss, which is in contrast to the requirement of Parity-Time (PT) symmetry to develop exceptional points based on gain and loss balance. The EPDs arise here by introducing symmetry breaking in a conventional chain of coupled resonators through coupling the chain of resonators to an adjacent uniform optical waveguide, which leads to unique modal characteristics that cannot be realized in conventional CROWs. Such remarkable characteristics include high quality factors (Q-factor) and strong field enhancement, even without any mirrors at the two ends of a cavity. We show for the first time the capability of CROWs to exhibit EPDs of various order; including the degenerate band edge (DBE) and the stationary inflection point (SIP). The proposed CROW of finite length shows enhanced quality factor when operating near the DBE, and the Q-factor exhibits an anomalous scaling with the CROW's length. We develop the theory of EPDs in such unconventional CROW using coupled-wave equations, and we derive an analytical expression for the dispersion relation. The proposed unconventional CROW concepts have various potential applications including Q-switching, nonlinear devices, lasers, and extremely sensitive sensors.Comment: 16 pages, 11 figure

Spontaneous Coronary Artery Dissection : The Phantom Menace

Articles © The authorsWe present a case of a 66-year-old lady with chest pain, without dynamic 12-lead electrocardiographic (ECG) changes and normal serial troponin. Coronary angiography revealed a linear filing defect in the first obtuse marginal branch of the circumflex artery indicating coronary artery dissection, with superadded thrombus. She was managed medically with dual antiplatelet therapy and has responded well. Spontaneous coronary artery dissection (SCAD) is a rare cause of cardiac chest pain, which can be missed without coronary angiography. Unlike most other lesions in patients with unstable symptoms, where coronary intervention with stenting is recommended, patients with SCAD generally fare better with conservative measures than with intervention, unless there is hemodynamic instability.Peer reviewe

Numeral Recognition Using Statistical Methods Comparison Study

The area of character recognition has received a considerable attention by researchers all over the world during the last three decades. However, this research explores best sets of feature extraction techniques and studies the accuracy of well-known classifiers for Arabic numeral using the Statistical styles in two methods and making comparison study between them. First method Linear Discriminant function that is yield results with accuracy as high as 90% of original grouped cases correctly classified. In the second method, we proposed algorithm, The results show the efficiency of the proposed algorithms, where it is found to achieve recognition accuracy of 92.9% and 91.4%. This is providing efficiency more than the first method

Developing Commitment Towards Change in Bureaucracies: The Case-Study of the Egyptian Civil Service Sector

This thesis examines the management of change in bureaucracies, with a study focus on the Egyptian civil service sector. The main research aims are to identify what are the main problems of the Egyptian civil service sector, identify the main barriers against the current change programmes undertaken by the Government of Egypt (GOE) and suggest ways to develop civil servants’ commitment towards those changes. Interview data was triangulated with archival documents and non-participant observation and were drawn from a sample of 33 civil servants working in the Egyptian Ministry of State for Administrative Development (MSAD) which is the civil service entity acting as the change agent responsible for managing the government administrative reforms plan in the civil service sector. All study participants were actually working in one of the change projects/programmes and had a minimum of 12 months of service in the civil service. Interviews were digitally-recorded and transcribed in the form of MS-Word documents, and data transcripts were analysed manually using MS-Excel worksheets and main research themes were developed and statistics drawn using those Excel worksheets. The main research findings suggested that the main problems of the Egyptian civil service sector are (1) the absence of a Reward and Punishment system, (2) the absence of a firm system of governance and control and (3) the current negative civil service culture. The research findings suggested that developing civil servants’ commitment towards change may be achieved by employee involvement and participation in the change process and the careful selection of inspirational change agents. The findings also suggested that change agents play an important role in inspiring civil servants to support change and that middle management is another crucial factor in the change move as it should act as liaison between change agents and employees

Trending topic extraction from social media

Social media has become the first source of information for many people. The amount of information posted on social media daily has become very vast that it became difficult to track. One of the most popular social media applications is Twitter. Users follow lots of news accounts, public figures, and their friends so they can be updated by the latest events around them. Since the dialect language and the style of writing differ from a region to another, our objective in this research is to extract trending topics for an Egyptian twitter user. In this way, the user can easily get at a glimpse of the trending topics discussed by the people he follows. To find the best approach achieving our objective, we investigate the document pivot and the feature pivot approaches. By applying the document pivot approach on the baseline data using tf-itf (term frequency-inverse tweet frequency) representation, repeated bisecting k-means clustering technique and extracting most frequent n-grams from each cluster we could achieve a recall value of 100% and F1 measure of 0.8. The application of the feature pivot approach on the baseline data using the content similarity algorithm to group related unigrams together, could achieve a recall value of 100% and F1 measure of 0.923. To validate our results we collected 12 different data sets of different sizes (200, 400, 600, and 1200) and from three different domains (sports, entertainment, and news) then applied both approaches to them. The average recall, precision and F1 measure values resulted from applying the feature pivot approach are larger than those achieved by applying the document pivot approach. To make sure this difference in results is statistically significant we applied the Two-sample one-tailed paired significance t-test that showed the results are significantly better at confidence interval of 90% The results showed that the document pivot approach could extract the trending topics for an Egyptian twitter user with an average recall value of 0.714, average precision value of 0.521, and average F1 measure value of 0.556 versus average recall, precision and F1 measure values of 0.981, 0.754, and 0.833 respectively, when applying the feature pivot approach. â€

Coastline Kriging: A Bayesian Approach

Statistical interpolation of chemical concentrations at new locations is an important step in assessing a worker's exposure level. When measurements are available from coastlines, as is the case in coastal clean-up operations in oil spills, one may need a mechanism to carry out spatial interpolation at new locations along the coast. In this paper we present a simple model for analyzing spatial data that is observed over a coastline. We demonstrate four different models using two different representations of the coast using curves. The four models were demonstrated on simulated data and one of them was also demonstrated on a dataset from the GuLF STUDY. Our contribution here is to offer practicing hygienists and exposure assessors with a simple and easy method to implement Bayesian hierarchical models for analyzing and interpolating coastal chemical concentrations

Integrating Islamic Cultural Identity Preservation in the Urban Fabric of the United States

The post-displacement phase of Islamic migrants in the urban fabric of the United States as a democratic country creates a bicultural identity. Muslims have been concerned about their identity preservation in the United States and integrating in the surrounding host community. This paper concentrates on what type of solution I can contribute, as an architect, to help in integrating Muslim population specially migrants at the post-displacement phase in the urban fabric of the United States. How can an architect help Muslim religious commonality connect in the larger United States Context? How do religious cultural buildings preserve and integrate an Islamic cultural Identity in the general cultural context of the United States? In addition, how do public spaces located in urban fabrics serve the integration process of Islamic culture with the surrounding cultural norms in order to be identified and well accepted by the community? In order to understand displaced minorities needs and concerns interviews are conducted. A brief explanation and analysis of the main Islamic lifestyle and ancient cities planning is also an important methodology in order to understand the effectiveness of Islamic cultural buildings at the United States in the identity preservation process. Inspired by my own personal experience I will explore and compare three case studies: Saudi Arabia – a strict Islamic country, Sudan – a moderate Islamic country, and Columbus, Ohio – a western urban society in the United States that is a non-Islamic democratic country. An empirical study will compare these three case studies through the lens of democracy, diversity and religion to explore how the Islamic Culture has been reformed and how religious minorities are preserving their own identities. My proposed methodology in order to find a solution, as an architect, is to create a loose public space where all different cultures connect and engage