Raman scattering studies and charge transport in polyfluorenes

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on November 21, 2007)Vita.Thesis (Ph. D.) University of Missouri-Columbia 2007.Blue-emitting polyfluorenes (PFs) have emerged as especially attractive [pi] conjugated polymers (CP) due to their strong blue emission and excellent electronic properties and thus great prospects for device applications. This project entails detailed Raman scattering studies and charge transport properties of two side chain substituted PFs: Poly(2,7-[9,9'-bis(2-ethylhexyl)] fluorene) (PF2/6) and Poly(9,9-(di-n,n-octyl) fluorene) (PF8). Raman scattering techniques as a function of thermal cycling are used to monitor the changes in the backbone and side chain morphology of PF8. Theoretical modeling of the vibrational spectra of single chain oligomers in conjunction with the experimental results demonstrate the incompatibility of the [beta] phase, a low energy emitting chromophore, with the overall crystalline phase in PF8. Further, electroluminescence and photoluminescence measurements from PF-based light-emitting diodes (LEDs) are presented and discussed in terms of the crystalline phases and chain morphologies in the PFs. Charge carrier injection and transport properties of PF-based LEDs are presented using current-voltage (I-V) characteristic which is modeled by a space-charge-limited conduction (SCLC) for discrete and continuous traps. PF2/6 with a high level of molecular disorder is an exemplary system for the SCLC model with discrete single level shallow traps. Charge transport as a function of sample thickness uncovers the origin of these traps. Temperature dependence of I-V and dc conductivity measurements suggest thermal assisted variable-range hopping transport instead of band transport in these materials. Raman scattering studies of PF2/6-based LEDs with doping and in the presence of injected and photo-generated charge carriers show increasing backgrounds with asymmetric Briet-Wigner Fano (BWF) line shapes, indicating strong electronphonon interactions.Includes bibliographical reference

Considerations in Designing Human-Computer Interfaces for Elderly People

As computing devices continue to become more heavily integrated into our lives, proper design of human-computer interfaces becomes a more important topic of discussion. Efficient and useful human-computer interfaces need to take into account the abilities of the humans who will be using such interfaces, and adapt to difficulties that different users may face – such as the difficulties that elderly users must deal with. Interfaces that allow for user-specific customization, while taking into account the multiple difficulties that older users might face, can assist the elderly in properly using these newer computing devices, and in doing so possibly achieving a better quality of life through the advanced technological support that these devices offer. In this paper, we explore common problems the elderly face when using computing devices and solutions developed for these problems. Difficulties ultimately fall into several categories: cognition, auditory, haptic, visual, and motor-based troubles. We also present an idea for a new adaptive operating system with advanced customizations that would simplify computing for older users

Perkembangan Pesantren Di Era Teknologi

This paper aims to discuss the possibility of boarding education institutions to respond to technological advances and information that can give a new color to its existence in Indonesia. By the general public, pesantren or islamic boarding school is still considered being left behind in term of technology mastery, particularly in the use of information technology to education. Whereas, the potential for improvement exists when Siskdiknas Act No. 20 of 2003 Article 30, paragraph 4, placed boarding position parallel with other educational institutions in Indonesia. Now, pesantren are not only identic with as educational institutions that teach religious sciences but also develop general science, including the use of information technology for education. Therefore, pesantren should not waste this opportunity. Pesantren should always update the information they use. With information technology pesantren can be helped disseminate information about the profile, activities and management schools in developing human resources and education

AGRESIVITAS DAN KONTROL DIRI PADA REMAJA DI BANDA ACEH

Meningkatnya kecenderungan kenakalan diantara remaja di Banda Aceh telah menjadi perhatian besar. Pola kenakalan remaja yang pada awalnya hanya berupa tawuran atau perkelahian antar pelajar semakin mengarah pada tindakan-tindakan yang tergolong kriminalitas seperti penganiayaan, penusukan, dan pemerkosaan. Kasus kenakalan remaja tersebut merupakan bentuk dari perilaku agresi yang disebabkan oleh kurangnya kontrol diri pada individu. Penelitian ini bertujuan untuk mengetahui hubungan antara agresivitas dan kontrol diri pada remaja di Banda Aceh. Agresivitas merupakan respon oleh individu yang memberikan hal tidak menyenangkan kepada orang lain. Sedangkan kontrol diri merupakan kemampuan individu untuk menentukan perilakunya berdasarkan standar tertentu seperti moral, nilai, dan aturan di masyarakat agar mengarah pada perilaku positif. Sampel pada penelitian ini berjumlah 270 remaja di Banda Aceh. Teknik pengambilan sampel menggunakan metode disproportional stratified random sampling. Hasil analisis data menggunakan teknik analisis data Pearson menunjukkan koefisien korelasi (r) sebesar -0,448 dengan nilai p = 0,000 (p < 0,05). Hipotesis yang diajukan diterima sehingga dapat disimpulkan bahwa terdapat hubungan negatif antara agresivitas dan kontrol diri pada remaja di Banda Aceh. Hal ini menunjukkan semakin tinggi kontrol diri maka semakin rendah agresivitas remaja di Banda Aceh. Remaja dengan tingkat kontrol diri yang tinggi akan mampu untuk mempertimbangkan konsekuensi dari perbuatan mereka dan dapat menghindari berperilaku agresif.Kata Kunci : Agresivitas, Kontrol Diri, Remaja

A Gossip Algorithm based Clock Synchronization Scheme for Smart Grid Applications

The uprising interest in multi-agent based networked system, and the numerous number of applications in the distributed control of the smart grid leads us to address the problem of time synchronization in the smart grid. Utility companies look for new packet based time synchronization solutions with Global Positioning System (GPS) level accuracies beyond traditional packet methods such as Network Time Proto- col (NTP). However GPS based solutions have poor reception in indoor environments and dense urban canyons as well as GPS antenna installation might be costly. Some smart grid nodes such as Phasor Measurement Units (PMUs), fault detection, Wide Area Measurement Systems (WAMS) etc., requires synchronous accuracy as low as 1 ms. On the other hand, 1 sec accuracy is acceptable in management information domain. Acknowledging this, in this study, we introduce gossip algorithm based clock synchronization method among network entities from the decision control and communication point of view. Our method synchronizes clock within dense network with a bandwidth limited environment. Our technique has been tested in different kinds of network topologies- complete, star and random geometric network and demonstrated satisfactory performance