Inspection criteria ensure quality control of parallel gap soldering

Investigation of parallel gap soldering of electrical leads resulted in recommendation on material preparation, equipment, process control, and visual inspection criteria to ensure reliable solder joints. The recommendations will minimize problems in heat-dwell time, amount of solder, bridging conductors, and damage of circuitry

Instrumentation, Data, And Algorithms For Visually Understanding Haptic Surface Properties

Autonomous robots need to efficiently walk over varied surfaces and grasp diverse objects. We hypothesize that the association between how such surfaces look and how they physically feel during contact can be learned from a database of matched haptic and visual data recorded from various end-effectors\u27 interactions with hundreds of real-world surfaces. Testing this hypothesis required the creation of a new multimodal sensing apparatus, the collection of a large multimodal dataset, and development of a machine-learning pipeline. This thesis begins by describing the design and construction of the Portable Robotic Optical/Tactile ObservatioN PACKage (PROTONPACK, or Proton for short), an untethered handheld sensing device that emulates the capabilities of the human senses of vision and touch. Its sensory modalities include RGBD vision, egomotion, contact force, and contact vibration. Three interchangeable end-effectors (a steel tooling ball, an OptoForce three-axis force sensor, and a SynTouch BioTac artificial fingertip) allow for different material properties at the contact point and provide additional tactile data. We then detail the calibration process for the motion and force sensing systems, as well as several proof-of-concept surface discrimination experiments that demonstrate the reliability of the device and the utility of the data it collects. This thesis then presents a large-scale dataset of multimodal surface interaction recordings, including 357 unique surfaces such as furniture, fabrics, outdoor fixtures, and items from several private and public material sample collections. Each surface was touched with one, two, or three end-effectors, comprising approximately one minute per end-effector of tapping and dragging at various forces and speeds. We hope that the larger community of robotics researchers will find broad applications for the published dataset. Lastly, we demonstrate an algorithm that learns to estimate haptic surface properties given visual input. Surfaces were rated on hardness, roughness, stickiness, and temperature by the human experimenter and by a pool of purely visual observers. Then we trained an algorithm to perform the same task as well as infer quantitative properties calculated from the haptic data. Overall, the task of predicting haptic properties from vision alone proved difficult for both humans and computers, but a hybrid algorithm using a deep neural network and a support vector machine achieved a correlation between expected and actual regression output between approximately ρ = 0.3 and ρ = 0.5 on previously unseen surfaces

Iron Smelting in Wollega, Ethiopia

The author is a graduate student affiliated with Addis Ababa University and the University of Bergen, who is currently concentrating on ethnoarchaeological studies in Ethiopia. He has carried out ethnographic field work on iron smelting traditions in West Ethiopia among the Oromo. Mr. Burka has also worked on reconstructing iron smelting techniques and traditions that had a long heritage in that region but declined from regular use over four decades ago. In this field report, he describes his direct observations of methods and traditions of ore mining and treatment, charcoal making, clay extraction, tuyere making, furnace construction, and smelting. This ethnoarchaeological study should provide highly valuable data for other researchers to use in formulating ethnographic analogies for use in archaeological investigations of iron production activities at other sites in Africa and the Americas

Qaalluu, Smith and Metal: Traditional Conflict Resolution Mechanisms in the Medium of Metals among the Oromo of Northeast Wollega, Ethiopia

The introduction of metals, particularly iron, has always been seen as an important stage of socio-cultural, economic, and political departure of human development. Nevertheless, since its appearance in the form of utilitarian or armaments, iron has occupied an ambiguous position in any society. It has played both the role of production by increasing fertility or prosperity, and destruction by furnishing the process of or terminating life. This ambivalent position of the material is also evident in the position of the workers in their respective societies. Consequently, its workers (the tumtuu) are both feared and respected. This ambiguous position/role of the material and the artisans has long attracted heated debates amongstarchaeometallurgists. Although the double roles of iron tools among the Oromo traditional believers in Wollega can never escape such debates, engagement in such a debate is beyond the scope of this article. This article, however, departs from the search for the destinations of iron tools once they left the production sites in the operational sequences i.e. traditional ritual site of the Qaalluu. The data for this discussion have emerged from my current ethnoarchaeometallurgical research in northeast Wollega, which aims to documenting different destination of iron/metal products after they left the cottage of the smiths. This article attempts to draw on the secular meaning of metal tools in order to attain the symbolic significance derived from it. Utilizing the data from traditional spiritual sites in northeast Wollega (Butaa Nadoo and Sagro Guddina), the article outlines the peaceful resolution of various forms of conflicts at the traditional ritual sites in the medium of metal tools or by invoking their symbolic value.Key words: Oromo, Wollega, Qalluu, Siida, Sibila Gurracha, conflict resolutio

Furnace Fire and Women: Agents of Iron Production and Social Reproduction

We are all part of the people of the world whose discourses are wrapped in traditions, stories or some kind of myth. These might be about its origin or the fabrics that maintained it together or features that distinguish it from the rest of its kind or the other neighbor or far distant people. The life of the Oromo groups who live in most part of western Ethiopia south of the Blue Nile is no different from such a socio-cultural scheme. The result of an ethnoarchaeological endeavor I have conducted on traditional craft since the late 2004 to 2011 has revealed a lot about the cosmology of the society, which can readily be transmitted in the medium of technical ceramic-furnace which itself becomes more socially comprehensible intertwined with fire and woman. The data that is derived during the operational sequences of iron production processes have served as the bases to provide the social/ideological/ritual context surround the trade. Whereas it appears that, the non-physical element of iron smelting is trivial, I would argue, at least in wider Ethiopian context and particularly among the Oromo, that the production of iron tools through the combination of physical elements cannot be fully comprehended in the absence of its social/ritual components. In this regard, the paper also relates the myth of origin of the first smith, his first product of metallurgy and the significance of this myth in conceptualizing production and reproduction in this society. This paper concludes that the knowledge of iron smelting is the product of the views of the people developed in other realms of socio-economic life such as human procreation or agricultural production either in the decoration of technical ceramics or activities and usage of or exchanges of words among the workers during production activities. Such rich experience lends a means of putting together ingredients resulting in a material culture made of iron.Key words: Ethiopia, Oromo, myth, furnace, fire, women, smith/smelte

Perceptual audio classification using principal component analysis

The development of robust algorithms for the recognition and classification of sensory data is one of the central topics in the area of intelligent systems and computational vision research. In order to build better intelligent systems capable of processing environmental data accurately, current research is focusing on algorithms which try to model the types of processing that occur naturally in the human brain. In the domain of computer vision, these approaches to classification are being applied to areas such as facial recognition, object detection, motion tracking, and others. This project investigates the extension of these types of perceptual classification techniques to the realm of acoustic data. As part of this effort, an algorithm for audio fingerprinting using principal component analysis for feature extraction and classification was developed and tested. The results of these experiments demonstrate the feasibility of such a system, and suggestions for future implementation enhancements are examined and proposed

The Quest for ‘Decolonizing’ and ‘Democratizing’ the Archaeologies in Ethiopia

The nature of the origin of Ethiopian archaeology1 (ies) is contestable on many grounds. It often overlaps with Pre/Aksumite archaeology. Ethiopian archaeology-so-called historic period, which in the main  concentrated on the northern Horn has suffered from spatial, temporal, and topical imbalances. However, few scholars have either considered it important or made attempts to redress it by broadening their field of vision. The misrepresentation in Ethiopian archaeology arises from the domination of expatriate scholars, who are of either Egyptology or Near Eastern training background. The absence of local training institutions that could produce capable and independent-minded indigenous archaeologists until very recently has also contributed to the problem. This paper argues that the only means of fair representations of regions  (democratization) in Ethiopian archaeology (ies) is by decolonizing it, which is the function of the production of capable and independent-minded indigenous archaeologists.Key words: decolonization, democratization, Ethiopia, historical archaeolog