Model-Based Approaches to Channel Charting

We present new ways of producing a channel chart employing model-based approaches. We estimate the angle of arrival theta and the distance between the base station and the user equipment rho by employing our algorithms, inverse of the root sum squares of channel coefficients (ISQ) algorithm, linear regression (LR) algorithm, and the MUSIC/MUSIC (MM) algorithm. We compare these methods with the training-based channel charting algorithms principal component analysis (PCA), Samson's method (SM), and autoencoder (AE). We show that ISQ, LR, and MM outperform all three in performance. The performance of MM is better than LR and ISQ but it is more complex. ISQ and LR have similar performance with ISQ having less complexity than LR. We also compare our algorithm MM with and algorithm from the literature that uses the MUSIC algorithm jointly on theta and rho. We call this algorithm the JM algorithm. JM performs very slightly better than MM but at a substantial increase in complexity. Finally, we introduce the rotate-and-sum (RS) algorithm which has about the same performance as the MM and JM algorithms but is less complex due to the avoidance of the eigenvector and eigenvalue analysis and a potential register transfer logic (RTL) implementation.Comment: 28 pages, 13 figures, 6 table

Bilateral investment treaties treatment of international capital movement: time for reform?

PhDWhile the freedom to move capital is necessary for foreign investors, the power of the state to regulate capital transfers is necessary to prevent volatile capital from causing financial crises as well as to mitigate such crises when they occur. Thus, in regulating international capital movement, a balance should be made between the right to transfer funds and the state’s right to protect the stability of its economy. It is in relation to achieving this balance that this thesis argues that bilateral investment treaties’ (BITs) regulation of capital transfers is deficient, both substantively and procedurally. On substance, this thesis identifies three substantive defects that affect obligations under BITs: absoluteness, immediacy, and breadth. First, many BITs adopt an absolute approach in liberalizing capital that does not permit any restrictions or exceptions, nor does it distinguish between different kinds of capital, or between the right to import capital and the right to repatriate capital. Second, the obligation to permit transfers is immediate and does not allow for a gradual liberalization of capital. Third, many BITs’ terms and obligations are broad and therefore vague, such as the broad definition of investment, or the obligation to grant fair and equitable treatment, which is also broad and interpreted in a manner that restricts the regulatory powers of the host state. Such results could have been partly mitigated if there were a dispute settlement mechanism with the power to create precedent and with it a clearer and more coherent body of rules. But BITs’ investor-state arbitration is also deficient since it consists of ad hoc tribunals, which are not bound by precedent; and their decisions are not generally subject to substantive review. This leads to an inconsistent and incoherent body of law that protects neither the state’s regulatory powers nor the legitimate expectation of investor

The branch point and course of the motor branch of the nerve to vastus medialis

STUDY OBJECTIVE: To investigate the exit point of the motor branch of the nerve to vastus medialis (mNVM) from the posterior division of the femoral nerve. An enhanced understanding of the origin and course of the mNVM will minimize the risk of anesthetizing it when performing a local anesthetic adductor canal nerve block for postoperative analgesia following total knee arthroplasty. METHODS: Anatomical donors, obtained through generous donation to the Anatomical Gift Program at Boston University School of Medicine (BUSM), were used in this study. Dissection of the mNVM was performed in 22 body donors (44 lower limbs). Before the dissection, the thigh length, from the anterior superior iliac spine (ASIS) to the base of the patella was measured. Additionally, following the dissection, the distance from the exit point of the mNVM to the base of the patella was measured. Then, the ratio between the two distances was calculated to provide a straightforward and efficient estimate of the mNVM branch point. SUMMARY OF RESULTS: The mean ± SD thigh length in the 44 lower limbs was 43 cm ± 2.9cm. The mNVM exited the posterior division of the femoral nerve 19.2 cm ± 1.90 cm superior to the base of the patella. The exit point of the mNVM from the posterior division of the femoral nerve was 0.56 ± 0.04 of the distance from the ASIS to the patella base. Pearson correlation was performed in order to examine the relationship between the distance of mNVM from the base of the patella to the total length of the thigh in the 44 limbs. This relationship was significant with P = 0.003. The One-Way Anova revealed no significant difference between male and female body donors in the ratio of the exit point of the mNVM relative to the length of the thigh. CONCLUSION: The mNVM emerges from the posterior division of the femoral nerve at 0.56 ± 0.04 of the thigh lengths as measured from the ASIS to the base of the patella. This finding provides clinicians with a practical and useful guide for determining the injection point for an adductor canal nerve block, a procedure utilized for postoperative analgesia following total knee arthroplasty. Protecting the mNVM during the block will avoid weakening the vastus medialis muscle and may result in greater patient participation in postoperative physical therapy, safer gait and may reduce the risk of falls

The effect of cold crystalloid versus warm blood cardioplegia on the myocardium during coronary artery bypass grafting

Background: The optimal cardioplegic solution is still debated. The objective of this study was to compare the effect of cold crystalloid versus warm blood cardioplegia on the myocardial injury during coronary artery bypass grafting. Methods: The study included 34 consecutive patients who underwent elective primary on-pump isolated coronary artery bypass grafting from 2016 to 2019. We randomly assigned the patients into two groups. Group (ICCC) (n= 17) received intermittent antegrade cold crystalloid cardioplegia and Group (IWBC) (n= 17) received intermittent antegrade warm blood cardioplegia. Results: There was no difference in the preoperative and operative variables between groups. The time taken by the heart to regain normal sinus rhythm was significantly longer in the cold crystalloid group (7.06 ± 1.8 vs. 2.17 ± 0.8 minutes, p<0.001) with a higher rate of reperfusion ventricular arrhythmia (35% versus 6%; p=0.03) compared to the warm blood cardioplegia group. Both coronary sinus acid production and lactate level were significantly higher in the warm blood group than in the cold crystalloid group (p< 0.001 and 0.043, respectively). The ischemic ECG changes and the severity of new segmental wall motion abnormalities were non-significantly different between both groups (p= 0.68 and 0.67, respectively). Postoperative CK-MB and cTnI levels in all-time points were not significantly different between groups (p= 0.46 and 0.37, respectively). ICU (2.29 ± 0.77 vs. 2.41 ± 0.87 days, p= 0.68) and hospital stay (9.28 ± 0.76 vs. 9.42 ± 0.88 days, p= 0.62) were non-significantly different between both groups. Conclusion: Intermittent antegrade cold crystalloid cardioplegia was associated with attenuated myocardial metabolism. However, it was associated with a longer time to regain normal sinus rhythm and more reperfusion ventricular arrhythmias. We did not find differences in the clinical and echocardiographic outcomes and cardiac enzymes between cold crystalloid and warm blood cardioplegia

Investigating Brexit Implications on the Irish Agri-Food Exports: A Simulation-Based Scenario Mapping Model

The Irish economy is highly dependent on the UK market with a total export value surpassing e 14 billion. Several reports have warned of severe bottlenecks at the Irish and British ports if new customs checks are reintroduced. A significant disruption is also expected to the traffic flow between Ireland and Britain because of the lack of proper checking infrastructure at some ports. This situation will cause devastating impact on the competitive advantage of various Irish exports to the UK market, particularly limited-shelf-life products. Hence, a simulation model has been developed to investigate three Brexit scenarios: 1) applying non-tariff barriers at ports, 2) replacing the UK Landbridge with direct routes to continental Europe, and 3) lack of checking infrastructure at the UK ports. The scenarios’ implications on the transportation time and shelf life of Irish Cheese exports to the UK are investigated, leading to one recommendable scenario

On The Solvability Of Some Diophantine Equations Of The Form ax+by = z2

The Diophantine equation ax+py = z2 where p is prime is widely studied by many mathematicians. Solving equations of this type often include Catalan’s conjecture in the process of proving these equations. Here, we study the non-negative integer solutions for some Diophantine equations of such family. We will use Mihailescu’s theorem (which is the proof of Catalan’s conjecture) and elementary methods to solve the Diophantine equations 16x −7y = z2, 16x − py = z2 and 64x − py = z2, then we will study a generalization where (4n)x − py = z2 and x, y, z,n are non-negative integers. By using Mihailescu’s theorem and a fundamental approach in the theory of numbers, namely the theory of congruence, we will determine the solution of the Diophantine equations 7x+11y = z2, 13x+17y = z2, 15x+17y = z2 and 2x+257y = z2 where x, y and z are non-negative integers. Also, we will prove that for any non-negative integer n, all non-negative integer solutions of the Diophantine equation 11n8x+11y = z2 are of the form (x, y, z) = (1,n,3(11) n2 ) where n is even, and has no solution when n is odd. Finally, we will concentrate on finding the solutions of the Diophantine equation 3x+ pmny = z2 where y = 1,2 and p > 3 a prime number

Post-Brexit Implications on Irish Freight Transport and Logistics Sector

The study quantifies the impact that new custom checks and Agri/SPS inspection procedures could have on agri-food supply chains. It is possible that these checks will be introduced at both EU27 and UK ports. The analysis shows the potential risks to the Irish agri-food supply chain. These risks are explained through a range of non-tariff barriers and Ireland/EU transport connectivity scenarios. There is potential for disruption in the long-established transportation routes between Ireland, the UK and Continental European markets. Direct shipping routes (i.e. links directly between Ireland and the EU26) have therefore been considered in this case. This consideration comes from the perspective of both practitioners in the field and experts from social, environmental, and economic disciplines. The study demonstrates how Irish agri-food supply chains are uniquely exposed to Brexit. Ireland has had strong ties with the UK market and has been a supplier for many decades. In 2018, agri-food exports from Ireland to the UK reached €5.6 billion, while imports from the UK yielded €4.5 billion. Overall, this provided Ireland with a trade surplus of more than €1 billion.1 In addition, about 38% of Irish unitised exports to Continental Europe transits via the UK land- bridge.2 Brexit poses an unprecedented risk to the competitive advantage that Irish agri-food products have cultivated in UK markets. This study reveals that the delivery time for all products will increase, in each scenario, which will diminish product shelf-life. This risk, of course, will affect both the value and quality of certain products, which in turn affects their competitiveness

Information-Theoretic Bounds for Steganography in Multimedia

Steganography in multimedia aims to embed secret data into an innocent looking multimedia cover object. This embedding introduces some distortion to the cover object and produces a corresponding stego object. The embedding distortion is measured by a cost function that determines the detection probability of the existence of the embedded secret data. A cost function related to the maximum embedding rate is typically employed to evaluate a steganographic system. In addition, the distribution of multimedia sources follows the Gibbs distribution which is a complex statistical model that restricts analysis. Thus, previous multimedia steganographic approaches either assume a relaxed distribution or presume a proposition on the maximum embedding rate and then try to prove it is correct. Conversely, this paper introduces an analytic approach to determining the maximum embedding rate in multimedia cover objects through a constrained optimization problem concerning the relationship between the maximum embedding rate and the probability of detection by any steganographic detector. The KL-divergence between the distributions for the cover and stego objects is used as the cost function as it upper bounds the performance of the optimal steganographic detector. An equivalence between the Gibbs and correlated-multivariate-quantized-Gaussian distributions is established to solve this optimization problem. The solution provides an analytic form for the maximum embedding rate in terms of the WrightOmega function. Moreover, it is proven that the maximum embedding rate is in agreement with the commonly used Square Root Law (SRL) for steganography, but the solution presented here is more accurate. Finally, the theoretical results obtained are verified experimentally.Comment: arXiv admin note: substantial text overlap with arXiv:2111.0496

Early Outcomes of video-assisted thoracoscopic management of secondary spontaneous pneumothorax

Background: Secondary spontaneous pneumothorax (SSP) is a presence of air in the pleural cavity due to underlying lung disease. Thoracotomy was the typical surgical technique for managing pneumothorax. However, video-assisted thoracoscopic surgery (VATS) became a standard for spontaneous pneumothorax treatment. Objectives: Assessment of VATS effectiveness and safety in the management of secondary spontaneous pneumothorax. Patients and methods: 96 patients with secondary pneumothorax underwent video-assisted thoracoscopic surgery for persistent air leak for more than 7 days or having a recurrent pneumothorax on the same side. A retrospective analysis of the patient's clinical characteristic data, perioperative outcome, and recurrence was performed. Results: 96 patients, the mean age was 61.1±11.7 years. 33 (32.3%) patients had a single attack and 63 (67.7%) patients had recurrent attacks of SPP. All patients had 3 ports of VATS surgery which included bullectomy and talc pleurodesis. Post-operative complications occurred in 37.5% of the patients. 31.3% experienced persistent air leak for more than 7 days after the surgery and 3.1 % had empyema due to prolonged air leak. Post-operative long hospital stay was significantly correlated with BMI (p=0.003), ASA grade (p=0.017), current smoking (p=0.016), and post-operative complication (p=0.001) in univariate analysis. In multivariate analysis, postoperative complication (p=0.001) and body mass index (BMI) was the only significant risk factors for a long hospital stay. Conclusion: Patients who had thoracoscopic surgery for the management of secondary spontaneous pneumothorax had a shorter length of hospitalization and a lower incidence of recurrence. High BMI and post-operative complications are risk factors for prolonged hospital stay

An empirical study on the thermal behavior of rice husk in eco-friendly brick for external walls of buildings

This study aims to analyze the behavior of natural and waste materials when applied to building brick for walls of residential buildings on the indoor temperatures and thermal comfort of residential buildings. In this study, small-scale residential rooms were built during a period of hot weather in Egypt. A comparison between models and a reference model using the traditional burned clay brick was conducted. The results indicate that the mud-brick leads to enhanced thermal behavior by 25% within comfort limits and the surface temperature difference could reach 4.3 K, whereas the compacted bricks achieve 15%, and the temperature difference was found to be 4 K; compared with the traditional fired bricks with 2.1 K surface temperature difference. Scanning electron microscopy showed large holes and cavities in the mud and compacted bricks. Whereas, in the fired clay brick small holes were observed; this difference in structure is hypothesized to lead to the difference in the thermal behavior of the bricks. The thermal conductivity(U), of the unfired mud-brick, was 0.27 W/m.K, U =0.32 W/m.K for compacted soil brick while burned bricks U=0.6 W/m.K. Based on the results, the combinations of rice husk as a waste material, mud, and compacted soil for brick lead to reducing cooling needs and sustainable building materials for new buildings in the hot and dry climate in Egypt