864 research outputs found

    Freight Rates and Productivity Gains in British Tramp Shipping 1869-1950

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    The standard source for pre-WWII global freight rate trends is the Isserlis British tramp shipping index. We think it is flawed, and that its sources offer vastly more information than the Isserlis aggregate contains. The new data confirm the precipitous decline in nominal freight rates before the World War I, but it also extends the series to the 1940s. Furthermore, our new series is linked to the post-World War II era (documented by David Hummels), so that we can be more precise about what has happened over the very long run. We also create route-specific deflators by using the prices of commodities transported. Previous scholars have deflated their nominal freight rate indices by a price index that includes tradables not carried on all routes and non-tradables not carried on any route. Our deflated indices offer a more effective measure of the contribution of declining freight rates to commodity-price convergence across trading regions. Using the pricedual method and new indices for factor prices, we then calculate total factor productivity growth pre-war and interwar for five global routes. Finally, we identify the sources of the total factor productivity growth.

    Quantum Revivals in Periodically Driven Systems close to nonlinear resonance

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    We calculate the quantum revival time for a wave-packet initially well localized in a one-dimensional potential in the presence of an external periodic modulating field. The dependence of the revival time on various parameters of the driven system is shown analytically. As an example of application of our approach, we compare the analytically obtained values of the revival time for various modulation strengths with the numerically computed ones in the case of a driven gravitational cavity. We show that they are in very good agreement.Comment: 14 pages, 1 figur

    Lessons Learnt from COVID-19: How Can We Prepare for Another Pandemic?

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    Relationship between Human Resource Management Practices and Perceived Performance of Employees in Jordanian Hospitals

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    The relationship between human resource management (HRM) practices and organizational performance is an important topic in the organizational sciences, but little research examining this relationship in hospital settings has been conducted. This study aims to quantify the effects of HRM practices on employee performance in 5 hospitals in Jordan. A descriptive survey design was used, wherein data was collected from all the staff of each hospital using questionnaires. The data were analyzed using descriptive statistics and correlation and regression analyses. The results demonstrate that HRM practices have an impact on performance, that Jordanian hospitals do not have effective HRM practices, and that compensation has the greatest impact on increasing an employee’s level of performance. Keywords: Jordanian Hospitals, human resource management practices, hospital performance

    Desain dan Pengembangan Backend Aplikasi Bantucari Menggunakan Microservices

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    BantuCari merupakan aplikasi untuk membantu seseorang apabila sedang kehilangan barang maupun menemukan barang. Aplikasi yang baik tentunya harus memiliki backend yang mumpuni. Salah satu cara untuk memnuhi backend mumpuni yakni dengan mengimplementasikan layanan microservices.  Salah satu cara untuk membuktikan dengan pengujian stress test menggunakan aplikasi Apache JMeter dan dibandingkan dengan services lainnya seperti VPS dan Shared Hosting. Dengan menggunakan parameter response time, troughput, sent, receive dan error untuk mengetahui keunggulan microservices. Dan hasil yang didapatkan pada penelitian ini dengan penerapan microservices dan pengujian dengan skenario yang ditentukan, arsitektur microservices lebih unggul dibandingkan dengan layanan yang lainnya

    On the degree conjecture for separability of multipartite quantum states

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    We settle the so-called degree conjecture for the separability of multipartite quantum states, which are normalized graph Laplacians, first given by Braunstein {\it et al.} [Phys. Rev. A \textbf{73}, 012320 (2006)]. The conjecture states that a multipartite quantum state is separable if and only if the degree matrix of the graph associated with the state is equal to the degree matrix of the partial transpose of this graph. We call this statement to be the strong form of the conjecture. In its weak version, the conjecture requires only the necessity, that is, if the state is separable, the corresponding degree matrices match. We prove the strong form of the conjecture for {\it pure} multipartite quantum states, using the modified tensor product of graphs defined in [J. Phys. A: Math. Theor. \textbf{40}, 10251 (2007)], as both necessary and sufficient condition for separability. Based on this proof, we give a polynomial-time algorithm for completely factorizing any pure multipartite quantum state. By polynomial-time algorithm we mean that the execution time of this algorithm increases as a polynomial in m,m, where mm is the number of parts of the quantum system. We give a counter-example to show that the conjecture fails, in general, even in its weak form, for multipartite mixed states. Finally, we prove this conjecture, in its weak form, for a class of multipartite mixed states, giving only a necessary condition for separability.Comment: 17 pages, 3 figures. Comments are welcom

    A Note on Normal Forms of Quantum States and Separability

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    We study the normal form of multipartite density matrices. It is shown that the correlation matrix (CM) separability criterion can be improved from the normal form we obtained under filtering transformations. Based on CM criterion the entanglement witness is further constructed in terms of local orthogonal observables for both bipartite and multipartite systems.Comment: 8 page

    Adapted LZW Protocol for ‎ ECG Data Compression

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    خوارزمية الـ(LZW) هي واحدة من طرق ضغط البيانات المستخدمة في عدة تطبيقات كضغط بيانات تخطيط القلب الكهربائي( ECG) لتقليل حجمها مما يسهل عملية نقلها عبر الشبكة. بما ان بيانات الـ(ECG) الخاصة بالمرضى تنقل عبر الشبكة طول الوقت لذلك ظهرت الحاجة الى تقليل حجمها من اجل ضمان وصولها بالسرعة الممكنة  لقاعدة البيانات. في هذه البحث نحن نهتم بطريقة الـ (LZW) التي هي واحدة من اهم واشهر طرق ضغط البيانات وقد اقترحنا بروتوكول لتحسين الطريقة التي تعتمدها خوارزمية الـ(LZW) في خزن المؤشرات الخاصة بالبيانات المضغوطة. البروتوكول المقترح يمكن ان يقلل حجم المؤشر لخوارزمية الـ(LZW). تم اعتماد خمس عينات اخذت من بنك المعلومات الخاص بـ(Physionet) لغرض اختبار البروتوكول المقترح. وقد اظهرت نتائج الاختبارت العملية ان البروتوكول المقترح يعطي نسبة ضغط افضل لبيانات الـ(ECG) مقارنة بطريقة الـ(LZW) الاصلية.Lempel–Ziv–Welch (LZW) is a data compression method, which is adopted by many applications likes Electrocardiography (ECG) data to reduce the size of transferred data. Because of the ECG data moves over the network all the time, which means there is a need to reduce its size to improve the network performance. In this paper, we concerned with the LZW method, which is one of the important and famous data compression method. We propose a protocol to improve the way in which the LZW saving an index for the compressed data. The proposed protocol could reduce the size of the index in LZW method. Five samples data groups provided by Physionet are used for evaluation. The experimental result shows that the proposed protocol can give best compression ratio compared with the original method
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