On the Statistics of Cognitive Radio Capacity in Shadowing and Fast Fading Environments (Journal Version)

In this paper we consider the capacity of the cognitive radio channel in different fading environments under a low interference regime. First we derive the probability that the low interference regime holds under shadow fading as well as Rayleigh and Rician fast fading conditions. We demonstrate that this is the dominant case, especially in practical cognitive radio deployment scenarios. The capacity of the cognitive radio channel depends critically on a power loss parameter, $\alpha$, which governs how much transmit power the cognitive radio dedicates to relaying the primary message. We derive a simple, accurate approximation to $\alpha$ in Rayleigh and Rician fading environments which gives considerable insight into system capacity. We also investigate the effects of system parameters and propagation environment on $\alpha$ and the cognitive radio capacity. In all cases, the use of the approximation is shown to be extremely accurate.Comment: Submitted to the IEEE Transactions on Wireless Commun. The conference version of this paper appears in Proc. IEEE CrownCom, 200

Interference and Deployment Issues for Cognitive Radio Systems in Shadowing Environments

In this paper we describe a model for calculating the aggregate interference encountered by primary receivers in the presence of randomly placed cognitive radios (CRs). We show that incorporating the impact of distance attenuation and lognormal fading on each constituent interferer in the aggregate, leads to a composite interference that cannot be satisfactorily modeled by a lognormal. Using the interference statistics we determine a number of key parameters needed for the deployment of CRs. Examples of these are the exclusion zone radius, needed to protect the primary receiver under different types of fading environments and acceptable interference levels, and the numbers of CRs that can be deployed. We further show that if the CRs have apriori knowledge of the radio environment map (REM), then a much larger number of CRs can be deployed especially in a high density environment. Given REM information, we also look at the CR numbers achieved by two different types of techniques to process the scheduling information.Comment: to be presented at IEEE ICC 2009. This posting is the same as the original one. Only author's list is updated that was unfortunately not correctly mentioned in first versio

PENGARUH TEKNIK PEMBELAJARAN KOOPERATIF TIPE TIME TOKEN ARENDS TERHADAP HASIL BELAJAR SISWA PADA MATA DIKLAT DASAR-DASAR KELISTRIKAN DI SMKN 1 SIDOARJO

Abstrak Penelitian ini bertujuan untuk mengetahui hasil belajar dan keterampilan sosial siswa dengan menggunakan teknik pembelajaran  kooperatif tipe time token arends dan hasil belajar dengan menggunakan model pembelajaran kooperatif tipe STAD (Student Team Achievement Division) pada mata diklat menerapkan dasar – dasar kelistrikan. Penelitian ini menggunakan desain penelitian “Quasi Experimental Design dengan jenis rancangannya adalah Nonequivalent Control Group Design. Populasi dan sampel dalam penelitian ini adalah seluruh siswa kelas X Program Keahlian Teknik Audio Video sebanyak 2 kelas yaitu kelas X TAV1 dan X TAV2 yang masing-masing kelas terdiri atas 36 siswa. Perangkat pembelajaran dalam peneletian ini terdiri dari Silabus, RPP dan  Modul. Kemudian untuk instrument penelitian ini adalah tes hasil belajar (soal pretest dan postest) dan lembar pengamatan keterampilan sosial siswa. Untuk mengetahui validitas perangkat pembelajaran dan instrumen penelitian digunakan rumus V dari AIKEN. Instrumen penelitian yang dipakai dalam pengumpulan data dalam penelitian ini adalah lembar pengamatan keterampilan sosial siswa dan tes hasil belajar dasar-dasar kelistrikan. Untuk mengetahui ketepatan dan kesahihan tes hasil belajar dilakukan uji validitas dan reliabilitas dengan kriteria validitas nilai V dari aiken mempunyai nilai v ≥ 0,70. kemudian teknik analisis data hasil belajar siswa untuk pretest yang digunakan adalah Uji-T dua pihak dengan taraf signifikan 5% sedangkan untuk hasil belajar siswa untuk postest yang digunakan adalah uji-T satu pihak dengan taraf signifikansi 5% Hasil validasi menunjukkan nilai validitas RPP adalah 0,81 termasuk dalam kriteria validitas yang valid, nilai validitas Modul adalah 0,78 termasuk dalam kriteria validitas yang valid, nilai validitas butir soal (Soal Pretest dan Postest) adalah 0,71 termasuk dalam kriteria validitas yang valid, dan nilai validitas untuk lembar pengamatan keterampilan sosial siswa adalah 0,72 termasuk dalam kriteria validitas yang valid. Jadi dapat disimpulkan bahwa perangkat pembelajaran dan instrumen penelitian tersebut layak digunakan. hasil penelitian dan pembahasan dapat disimpulkan yaitu dengan membandingkan ttest dan tTabel pada analisis postest, Diketahui ttest sebesar 6,783 dan ttabel = t(1-α) = t(1-0,05) = t(0,95) dengan derajat kebebasan (dk) = n1 + n2 -2 = 70. Nilai ttabel adalah 1,67. Maka nilai ttest >  nilai ttabel dengan tingkat signifikansi sebesar 5 %. Sehingga dapat disimpulkan H0 di tolak dan H1 terima, yaitu hasil belajar siswa yang menggunakan teknik Pembelajaran Kooperatif tipe Time Token Arends secara signifikan lebih baik dari pada siswa yang menggunakan model pembelajaran kooperatif tipe STAD (Student Team Achievement Division). Kata kunci : Model pembelajaran kooperatif, kooperatif tipe time token arends, Hasil belajar. . Abstract This study aims to determine learning outcomes and social skills of students using cooperative learning techniques based on Time Token Arends type compared with learning outcomes using cooperative learning techniques based on STAD (Student Team Achievement Division) type on the basic competence of electricity. The design of this research study is "Quasi Experimental Design” with the specific type of design is Nonequivalent Control Group Design. Population and samples in this study were all students of class X Audio Video Engineering Skills Program with 2 classes, each of class is X-TAV1 and X-TAV2, each class consists of 36 students. Instrument in this research consists of lesson plans, modules, achievement test (pretest and posttest questions), and student social skills observation sheet. To test the validity of the research instrument used AIKEN formula. The research instrument that used for data collection in this study was the students social skills observation sheet and learning outcomes test. To determine the accuracy and validity of the achievement test, the instrument must require test of the validity and reliability with sort of criteria of validity from index V from AIKEN outcome  above v ≥ 0,70. after that, analysis of the data techniques for student learning outcomes which first time test which used pretest questions is using 2-tailed sample T-test with significance level of 5%, while for student learning outcomes for the second time test which used  posttest questions is using one sample T-test with a significance level of 5% The results of instrument validity it can be seen that the value of the validity of the lesson plan instrument was 0.81 which in the criteria of validity is very high, the value of the validity of the module instrument was 0.78 which in the criteria of validity is valid, the value of the validity of the pretest and postest questions instrument was 0.71 which in the criteria of validity is valid, and the value of the validity for students' social skills observation checklist was 0.72 which in the criteria of validity is valid. So it can be concluded that the research instrument is proper for use in research. The result of research and discussion can be concluded by comparing t-test and t-table at posttest analysis, t-test known for t-table = 6.783 and t (1-α) = t (1-.05) = t (0.95) with degrees of freedom (df ) = n1 + n2 -2 = 70, t-table value is 1.67. The value of t-test > value of t-table with a significance level of 5%. Therefore we can conclude H0 is rejected and H1 accepted, the student learning outcomes using this Cooperative Learning technique based on Time Token Arends type significantly better than students using cooperative learning technique based on STAD type (Student Team Achievement Division).Keywords: cooperative learning model, cooperative learning with time token arends type, learning outcome

Level Crossing Rates of Interference in Cognitive Radio Networks

The future deployment of cognitive radios is critically dependent on the fact that the incumbent primary user system must remain as oblivious as possible to their presence. This in turn heavily relies on the fluctuations of the interfering cognitive radio signals. In this letter we compute the level crossing rates of the cumulative interference created by the cognitive radios. We derive analytical formulae for the level crossing rates in Rayleigh and Rician fast fading conditions. We approximate Rayleigh and Rician level crossing rates using fluctuation rates of gamma and scaled noncentral $\chi^2$ processes respectively. The analytical results and the approximations used in their derivations are verified by Monte Carlo simulations and the analysis is applied to a particular CR allocation strategy.Comment: submitted to the IEEE Transactions on Wireless Communication

ATR-FTIR spectroscopy detects alterations induced by organotin(IV) carboxylates in MCF-7 cells at sub-cytotoxic/-genotoxic concentrations.

The environmental impact of metal complexes such as organotin(IV) compounds is of increasing concern. Genotoxic effects of organotin(IV) compounds (0.01 μg/ml, 0.1 μg/ml or 1.0 μg/ml) were measured using the alkaline single-cell gel electrophoresis (comet) assay to measure DNA single-strand breaks (SSBs) and the cytokinesis-block micronucleus (CBMN) assay to determine micronucleus formation. Biochemical-cell signatures were also ascertained using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. In the comet assay, organotin(IV) carboxylates induced significantly-elevated levels of DNA SSBs. Elevated micronucleus-forming activities were also observed. Following interrogation using ATR-FTIR spectroscopy, infrared spectra in the biomolecular range (900 cm-1 – 1800 cm-1) derived from organotin-treated MCF-7 cells exhibited clear alterations in their biochemical-cell fingerprint compared to control-cell populations following exposures as low as 0.0001 μg/ml. Mono-, di- or tri-organotin(IV) carboxylates (0.1 μg/ml, 1.0 μg/ml or 10.0 μg/ml) were markedly cytotoxic as determined by the clonogenic assay following treatment of MCF-7 cells with ≥ 1.0 μg/ml. Our results demonstrate that ATR-FTIR spectroscopy can be applied to detect molecular alterations induced by organotin(IV) compounds at sub-cytotoxic and sub-genotoxic concentrations. This biophysical approach points to a novel means of assessing risk associated with environmental contaminants

Pengaruh Kapasitas Sumber Daya Manusia, Pemanfaatan Teknologi Informasi, Pengendalian Intern Akuntansi, dan Komitmen Organisasi terhadap Keterandalan Pelaporan Keuangan Pemerintah Daerah (Survei pada Skpd Se-kabupaten Kuansing)

This research aims to examine the effect of , Human resource capacity, Information technology utilization, Accounting intern control and comitmen organisation. This research is motivated by the fact that the government financial reporting should provide information on reliable and timely in assessing accountability and decision making of various parties. All variables in this research were measured using a likert scale.The data in this study is the primary data obtained from questionnaires distributed directly to the respondents. Data collected from 54 respondents who are working at financial reporting staff in SKPD of Kuansing regency. The method of data analysis used to test the hypothesis is multiple regression analysis using the program SPSS 20 version.The results of this study is showed that capacity of human resources, utilization of technology, internal accounting controls, and comitmen organisation influence to the reliability of financial reporting in Kuansing regency.Keywords: The reliability of financial reporting, Human resource capacity, Information technology utilization, Internal control system and comitmen organisatio

Kinerja Keuangan Pada USAha Kecil Menengah Penerima Dana Bergulir Modal Kerja Di Kabupaten Kediri

The objective of research is to analyze the financial performance of UKM beforeand after receiving Dana Bergulir Modal Kerja. The main data that is collected as secondarydata. Descriptive analysis is used to investigation on company characteristic has received DanaBergulir Modal Kerja, while the financial and marketing are analyzed by using quantitaveanalysis which used financial ratio analysis and different t-test. Result of analysis showed thatthe organized of Dana Bergulir Modal Kerja done by the businessmen who has right target.There's only one financial ratio index that has real differenciates statistically that is net profitmargin showed that almost the big of UD decreased on that index. Statistically the sellingturnover after receiving Dana Bergulir Modal Kerja. The right empowerment for UKM by DanaBergulir Modal Kerja is done by “tanggung renteng”system

Performance of Cognitive Radio Systems with Imperfect Radio Environment Map Information

In this paper we describe the effect of imperfections in the radio environment map (REM) information on the performance of cognitive radio (CR) systems. Via simulations we explore the relationship between the required precision of the REM and various channel/system properties. For example, the degree of spatial correlation in the shadow fading is a key factor as is the interference constraint employed by the primary user. Based on the CR interferers obtained from the simulations, we characterize the temporal behavior of such systems by computing the level crossing rates (LCRs) of the cumulative interference represented by these CRs. This evaluates the effect of short term fluctuations above acceptable interference levels due to the fast fading. We derive analytical formulae for the LCRs in Rayleigh and Rician fast fading conditions. The analytical results are verified by Monte Carlo simulations.Comment: presented at IEEE AusCTW 2009. Journal versions are under preparation. This posting is the same as the original one. Only author's list is updated that was unfortunately not correctly mentioned in the first versio