Generalised hyperbolicity in spacetimes with string-like singularities

In this paper we present well-posedness results of the wave equation in $H^{1}$ for spacetimes that contain string-like singularities. These results extend a framework able to characterise gravitational singularities as obstruction to the dynamics of test fields rather than point particles. In particular, we discuss spacetimes with cosmic strings and the relation of our results to the Strong Cosmic Censorship Conjecture.Comment: Accepted for publication in Classical and Quantum Gravit

Green operators for low regularity spacetimes

In this paper we define and construct advanced and retarded Green operators for the wave operator on spacetimes with low regularity. In order to do so we require that the spacetime satisfies the condition of generalised hyperbolicity which is equivalent to well- posedness of the classical inhomogeneous problem with zero initial data where weak solutions are properly supported. Moreover, we provide an explicit formula for the kernel of the Green operators in terms of an arbitrary eigenbasis of H 1 and a suitable Green matrix that solves a system of second order ODEs

Modeling spin transport in electrostatically-gated lateral-channel silicon devices: role of interfacial spin relaxation

Using a two-dimensional finite-differences scheme to model spin transport in silicon devices with lateral geometry, we simulate the effects of spin relaxation at interfacial boundaries, i.e. the exposed top surface and at an electrostatically-controlled backgate with SiO_2 dielectric. These gate-voltage-dependent simulations are compared to previous experimental results and show that strong spin relaxation due to extrinsic effects yield an Si/SiO_2 interfacial spin lifetime of ~ 1ns, orders of magnitude lower than lifetimes in the bulk Si, whereas relaxation at the top surface plays no substantial role. Hall effect measurements on ballistically injected electrons gated in the transport channel yield the carrier mobility directly and suggest that this reduction in spin lifetime is only partially due to enhanced interfacial momentum scattering which induces random spin flips as in the Elliott effect. Therefore, other extrinsic mechanisms such as those caused by paramagnetic defects should also be considered in order to explain the dramatic enhancement in spin relaxation at the gate interface over bulk values

GDSS (Group Decision Support System): Penentuan Passing Grade dengan Menggunakan Metode Utility – based Agent dan DELPHI (Studi Kasus: Penerimaan Mahasiswa Baru STT Telkom) GDSS ( Group Decision Support System ): Determining of Passing Grade uses Utility

ABSTRAKSI: Group Decision Support System merupakan suatu fasilitas pengambilan keputusan berbasis komputer dan jaringan dalam sebuah kelompok untuk memperoleh suatu pertimbangan keputusan bersama. Di dalam Group Decision Support System, proses pengambilan keputusan dapat dianalogikan sebagai sebuah pertemuan kelompok yang sedang melakukan pengambilan suara terbanyak untuk menghasilkan sebuah keputusan bersama. Melalui Group Decision Support System ini, keterbatasan jarak dan waktu dalam menganalisa dan mengambil keputusan lebih dapat teratasi. Mengikuti tradisi sebelumnya ataupun tradisi perguruan tinggi - perguruan tinggi lain, penentuan standar passing grade dalam tes Penerimaan Mahasiswa Baru di Sekolah Tinggi Teknologi Telkom masih dilakukan dengan pertimbangan yang tidak jelas dari pihak dewan jurusan masing-masing. Dampaknya, para peserta tes mengerjakan tes mereka tanpa suatu target nilai tertentu, sehingga mereka juga tidak memiliki strategi yang cukup jelas dalam mengerjakan tes-nya. Analisa dan implementasi aplikasi sistem pendukung pengambilan keputusan yang dikembangkan ini bertujuan untuk membantu rapat dewan dalam menentukan passing grade berdasarkan analisa kemungkinan atau prediksi kualitas dengan menggunakan metode utility – based agent dan DELPHI. Keputusan passing grade dapat dihasilkan secara real time bagi pihak dewan, dapat memberikan target nilai yang jelas bagi para peserta ujian menuju standar kelulusan tes tersebut, maupun dapat memberikan kriteria kelulusan yang dapat dipertanggungjawabkan.Kata Kunci : Group Decision Support System, passing grade, utility – based agent, DELPHI, dan real time.ABSTRACT: Group Decision Support System representing a decision making facility based on computer and network in a group to obtain a consideration of decision. In Group Decision Support System, decision-making processes earn analogy like a group of meeting which in pursuance of voting to a decision with. Through this Group Decision Support System, limitation of time and distance in analysing and taking decision can be more overcame. Following previous tradition or other universities‟ tradition, determination of standard elegibility of passing grade in New Selection Student for University at Telkom School of Engineering still be done with ill defined consideration of each majors council side. Its impact, all testees do their test without a certain value goals; and so they do not have clear strategy in doing their test. These analysis and implementation of application for decision support system which has being developed aim to assist council meeting in determining correct passing grade pursuant to possibility analysis or best quality prediction by using method of utility – based agent and of DELPHI. Decision of passing grade can be released on real time to council side, it can give clear value goals to all testees as a standard passing grade of the test, and also can give criterion pass of which can be justified.Keyword: Group Decision Support System, passing grade, utility – based agent, DELPHI, and real time

SISTEM INFORMASI PENDATAAN PESERTA DIDIK SMK BAGIMU NEGERIKU SEMARANG BERBASIS WEB APPLICATION

Efficiency is very important in all things, including the learners to collect data as it exists in every educational institution. With the development of information technology, the efficiency can be easily applied with the application of information technology. So with the application of information technology is expected all data management activities of learners are not done by hand. Therefore, the logging information systems manufacture learners are expected to facilitate, accelerate the TU staff in conducting the data inputting new learners, learner data search and data changes learners. So that the efficiency of the data management activities of learners can be achieved with the help of information systems data collection learners. This information system built using the PHP programming language and MySQL database is used, while in the design of display design using Adobe Dreamweaver CS5. The system is designed to use DFD (Data Flow Diagram). This system is built with the aim of facilitating the TU staff in data management activities learners SMK Bagimu Negeriku Semarang. Facilities contained in this system include: TU staff login as admin of this system, new student data input, learners perform all data and perform based on grade level, department, gender and learners with mutation status, then edit the data of participants learners and learners find data desired. In addition to facilitating the TU staff in data management activities of learners, but also expected to provide added value to the administration of SMK Bagimu Negeriku Semarang in implementing a paperless office

STUDI DESKRIPTIF MENGGAMBARKAN PERCEIVED VALUE WISATAWAN NUSANTARA DAN WISATAWAN NASIONAL TERHADAP BIRO PERJALANAN DI SURABAYA

Abstrak - Tujuan penelitian ini adalah menggambarkan perceived value wisatawan nusantara dan wisatawan nasional yang menggunakan biro perjalanan di Surabaya. Penelitian ini adalah berjenis riset deskriptif, Dimensi dari perceived value yaitu fungtional value of the travel agency (installations), functional value of the contact personnel of the travel agency (professionalism), functional value of the tourism package purchased (quality), fungtional value price, emotional value, dan social value. Sumber data yang di gunakan dalam penelitian ini adalah penelitian berupa kuesioner yang memperoleh data mengenai penilaian perceived value pada biro perjalanan di Surabaya. Secara keseluruhan, persepsi responden terhadap perceived value wisatawan nusantara dan wisatawan nasional yang menggunakan biro perjalanan di Surabaya adalah baik. Dimensi functional value of the tourism package purchased (quality) adalah dimensi yang dipersepsikan paling baik karena dengan nilai rata- rata tertinggi diantara dimensi perceived value lainnya. Kata kunci: Pariwisata, perceived value, wisatawan Abstract - The goal of this study is to describe the perceived value of national tourists and travelers who use travel agents in Surabaya. This assessment is descriptive research manifold. The dimensions of perceived value that is fungtional value of the travel agency (installations), functional value of the contact personnel of the travel agency (professionalism), functional value of the tourism package purchased (quality), fungtional price value, emotional value and social value . Source of data used in this study was a questionnaire study to obtain data on the perceived value assessment at a travel agency in Surabaya. Overall, respondents' perceptions of perceived value tourists and national tourists who use a travel agency in Surabaya is good. Dimensional functional value of the tourism package purchased (quality) is the dimension of the perceived best because the average value of the highest among other perceived value dimensions. Keywords: Tourism, perceived value, tourist

The Larmor clock and anomalous spin dephasing in silicon

Drift-diffusion theory - which fully describes charge transport in semiconductors - is also universally used to model transport of spin-polarized electrons in the presence of longitudinal electric fields. By transforming spin transit time into spin orientation with precession (a technique called the "Larmor clock") in current-sensing vertical-transport intrinsic Si devices, we show that spin diffusion (and concomitant spin dephasing) can be greatly enhanced with respect to charge diffusion, in direct contrast to predictions of spin Coulomb-drag diffusion suppression.Comment: minor edits and updated ref