Digital Image Ballistics from JPEG Quantization: A Followup Study

The lossy JPEG compression scheme employs a quantization table that controls the amount of compression achieved. Because different cameras typically employ different tables, a comparison of an image\u27s quantization scheme to a database of known cameras affords a simple technique for confirming or denying an image\u27s source. This report describes the analysis of quantization tables extracted from 1,000,000 images downloaded from Flickr.com

Common causes of failure of pneumatic distributors in high precision pneumatic seeders: Proposals towards predictive maintenance

Modern precision pneumatic drills (1-500 kg/ha) used in the cultivation of high density crops such as winter cereals (up to 400 plants/m2) are very high performance equipment that triple the working width (up to 9m) and rates (up to 14 km/h) compared to those used fifteen years ago. Most of enterprises commercialize such devices using as cornerstone a central pneumatic distributor in combination with a large number of radial outlets (24-48). In spite of the unquestionable advantages of these devices with regard to more conventional gravitational distributors, the main drawback remains the lack of transversal uniformity which has proven to be fairly sensitive to seed size and shape, to slight air flow changes related to partial obstructions of outlets, elbows and grips in discharge outlets, or vibrations and inclinations of the central distributor, as well associated to inadequate maintenance of the machine by untrained operators. Moreover, the lack of behavior predictability derives in a certain discredit of the pneumatic procedure. This work proposes a theoretical-empirical methodology to analyze the pneumatic circuit and its interaction with a variety of seeds types to be delivered, and selected operational machinery settings, within the aim of elaborating a test protocol which combined with low cost instrumentation will serve a base for predictive maintenance. Experimental data gathered in static and dynamic tests performed by the authors on at least two different seeders together with published information available on technical papers will be reviewed and used for further discussion on reliable diagnosis procedure

High Altitude Ballooning for Space and Atmospheric Observation

The purpose of our project was to conduct a series of high altitude balloon experiments on student-designed launch platforms. Many design goals were considered, including, but not limited to: horizontal control for helium weather balloons, tethered camera platforms (controlled and passive), rocket and glider payloads, self-stabilizing platforms, high-definition video platforms, and miscellaneous data collection. Over the course of the project, the High Altitude Ballooning Group completed two successful high altitude launches and several workshops on payload design and microcontroller programming. We have also conducted tests on tethered camera payloads, including field tests in Alaska for a related JPL study on imaging methane seeping from under frozen lakes

Designing product list on E-commerce web sites: The effect of sorting on consumer decision

Ph.DDOCTOR OF PHILOSOPH

Diagnosis of anal human papillomavirus infection: polymerase chain reaction or cytology?

Summary Objectives To investigate the relationship between human immunodeficiency virus (HIV)-positive and HIV-negative patients engaging in promiscuous behaviors and anal human papillomavirus (HPV) infection diagnosed by polymerase chain reaction (PCR) and cytology. Methods Fifty-six HIV-positive patients and 49 HIV-negative patients who engaged in sexually promiscuous behavior were enrolled in the study. We performed cytological exams using the Pap smear and PCR for HPV-DNA detection, with identification of oncogenic strains. The 2001 Bethesda System terminology was used for the cytological exams. We also evaluated the immunologic status of the HIV-infected patients. Results PCR positivity for HPV-DNA was higher in the group of HIV-positive patients than in the group of HIV-negative patients with a statistically significant difference. In contrast we did not find any statistically significant difference by cytological exam. Oncogenic strains were equally distributed in the two groups. Conclusions Our results indicate the importance of the cytological exam for anal HPV screening in the population at high risk of sexually transmitted disease and that HPV-DNA PCR can be used only as adjunct test

A jump-growth model for predator-prey dynamics: derivation and application to marine ecosystems

This paper investigates the dynamics of biomass in a marine ecosystem. A stochastic process is defined in which organisms undergo jumps in body size as they catch and eat smaller organisms. Using a systematic expansion of the master equation, we derive a deterministic equation for the macroscopic dynamics, which we call the deterministic jump-growth equation, and a linear Fokker-Planck equation for the stochastic fluctuations. The McKendrick--von Foerster equation, used in previous studies, is shown to be a first-order approximation, appropriate in equilibrium systems where predators are much larger than their prey. The model has a power-law steady state consistent with the approximate constancy of mass density in logarithmic intervals of body mass often observed in marine ecosystems. The behaviours of the stochastic process, the deterministic jump-growth equation and the McKendrick--von Foerster equation are compared using numerical methods. The numerical analysis shows two classes of attractors: steady states and travelling waves.Comment: 27 pages, 4 figures. Final version as published. Only minor change

考古資料からみた中世集落における消費活動 : 草戸干軒町道跡における資料形成過程の分析（5. 草戸に見る流通と消費）

中世の消費遺跡をめぐる考古学的研究では、近年、資料の計量分析がさかんに行われ、数多くの成果が蓄積されつつある。しかしその一方で、分析結果を解釈し、過去の人間活動を復元するための方法は十分に論じられてはいない。筆者は、考古資料から人間の消費活動を復元するためには、資料の形成過程についての分析が重要な役割を果たすと考えており、本稿ではまずMichael Schifferによる資料形成過程の概念を紹介した。Schifferは、考古資料に示される過去の人間活動の痕跡は当時から変化せず現代にもたらされたものではなく、さまざまな文化的・非文化的変換作用を経たものだと説く。さらに、変換作用が引き起こされる状況は「機能的文脈（現実の社会における関係）」と「考古学的文脈（遺跡・遺構における関係）」とに区分できることなどを示している。これらの指摘は、日本中世における消費活動を考古学的に分析する上でも参考になる点が多い。形成過程分析の具体的事例として、草戸千軒町遺跡（広島県福山市）から出土した輸入陶磁器・滑石製石鍋・木製食膳具の分析を試みた。分析に際しては、集落に搬入された消費財がどのような過程を経て廃棄、あるいは相続されるかを示す「搬入と廃棄のモデル」を設定した。このモデルに基づいて資料形成過程を解釈することにより出土資料の計量分析結果に認められるいくつかの事象が、過去の人間集団の消費活動をどのように反映しているのかが推測できるようになる。検討の結果、耐久消費財はそれが生産され、流通した時期に多くは廃棄されないこと、生活環境の変化を契機に多くの耐久消費財が廃棄されることなどが、具体的な出土状況に即して説明できるようになった。また、草戸千軒の集落における消費財廃棄のパターンから、限定された空間内で密度の高い消費活動が行われていたことを指摘し、これが集落の「都市的」な特質の一端を示していると考えた。As for the archaeological studies on Japanese medieval consumption sites, quantitative analyses have been extensively done and data have been accumulated. However, interpretation of data and methods of reconstructing human activities in the past have not been fully discussed.In order to reconstruct human activities from archaeological materials, the author of this paper considers it important to understand formation processes of these records. Accordingly, the fundamental concept of formation processes of archaeological records advocated by Michael SCHIFFER is presented first in this paper. Then, the author deals with the Kusado Sengen-cho site (Fukuyama City, Hiroshima Prefecture) a settlement from the mid-thirteenth century to the early sixteenth century. He analyzes how imported ceramics, stone pans made of talc and wooden tableware from the site were thrown into the discard in the settlement. As a result, the following facts are apparent; durable consumer goods were rarely discarded during the period when they were produced and circulated, and were inherited to the next generation in the systemic context, then changes of environment including ones in the settlement pattern were the moments of abandoning many durable consumer goods.Judging from the patterns of disposal in the Kusado Sengen settlement revealed from the above analysis, one can assume that intensive consuming activities were going on in limited space, which is considered to have shown a part of urban characteristics of this settlemen

Sembradoras Gil 5032 y 6040, la mejora continua aplicada al diseño

Este artículo presenta una nueva aproximación al conocimiento de las sembradoras neumáticas en líneas a chorrillo. Partimos de la descripción del diseño realizado en primera persona por la empresa española Julio Gil Águeda e Hijos, y proseguimos con el empleo de un manómetro diferencial tipo Pitot, para caracterizar y comparar el funcionamiento de los circuitos neumáticos en los modelos GIL 5032 (5 m de ancho) y 6040 (6 m de ancho). Su diversa configuración: 4 filas y 32 brazos en el primer caso, respecto a 3 filas y 40 brazos en el segundo, refleja su distinta funcionalidad: adaptación a elevados niveles de rastrojo (vocación de evitar embozos), respecto a una mayor uniformidad neumática ajustada a un suelo previamente labrado

High Altitude Ballooning for Space and Atmospheric Observation

The purpose of our project was to conduct a series of high altitude balloon experiments on student-designed launch platforms. Many design goals were considered, including, but not limited to: horizontal control for helium weather balloons, tethered camera platforms (controlled and passive), rocket and glider payloads, self-stabilizing platforms, high-definition video platforms, and miscellaneous data collection. Over the course of the project, the High Altitude Ballooning Group completed two successful high altitude launches and several workshops on payload design and microcontroller programming. We have also conducted tests on tethered camera payloads, including field tests in Alaska for a related JPL study on imaging methane seeping from under frozen lakes