Experimental validation of clock synchronization algorithms

The objective of this work is to validate mathematically derived clock synchronization theories and their associated algorithms through experiment. Two theories are considered, the Interactive Convergence Clock Synchronization Algorithm and the Midpoint Algorithm. Special clock circuitry was designed and built so that several operating conditions and failure modes (including malicious failures) could be tested. Both theories are shown to predict conservative upper bounds (i.e., measured values of clock skew were always less than the theory prediction). Insight gained during experimentation led to alternative derivations of the theories. These new theories accurately predict the behavior of the clock system. It is found that a 100 percent penalty is paid to tolerate worst-case failures. It is also shown that under optimal conditions (with minimum error and no failures) the clock skew can be as much as three clock ticks. Clock skew grows to six clock ticks when failures are present. Finally, it is concluded that one cannot rely solely on test procedures or theoretical analysis to predict worst-case conditions

Friends, Neighbours and Distant Partners: Extending or Decentring Family Relationships?

[No abstract][No keywords]

How do the Life Stories of Non-Traditional Students Impact Their Educational Journeys

The research question highlights the importance of personal narrative and explores the notion that reframing one’s story can have a strong impact on future success. The author discusses research pertaining to disconnected learners and examines the way in which personal stories influence classroom motivation. The data collection process takes an autobiographical approach as three non-traditional students share their educational life histories. Students’ stories are comprehensively explored through interviews, a review of student records, and observations. Each documented educational journey emphasizes the significance of individual stories and the importance of acknowledging the unique struggles faced by non-traditional students

Reconcevoir le délire

Les délires sont des composantes cruciales de nombreux troubles psychiques, surtout la schizophrénie. Que sont les délires ? Selon l’opinion courante, il s’agit d’un type de croyance, plus précisément, une croyance pathologique. Malheureusement, l’opinion courante ne correspond pas rigoureusement, dans tous les cas, à la pratique clinique, où l’expression « délire » est souvent appliquée à des états qui ne sont pas des croyances. Nous examinons les raisons pour lesquelles des états qui ne sont pas des croyances peuvent être considérés comme des délires. Nous soutenons que les délires sont des structures complexes d’attitudes d’ordre supérieur et inférieur. Ils constituent un type spécifique de défaillance de la connaissance et de la gestion de soi. Nous fournirons une description du type en question. Notre point de vue implique sur le plan conceptuel que les croyances ne sont pas essentielles aux délires.Delusions are critical components in a number of mental disorders, schizophrenia formost. What are they ? The standard view is that they are a type of belief — a pathological belief. Unfortunately, the standard view does not consistently correspond to clinical practice, where the term « delusion » often applies to non-beliefs. We review the case for saying that non-beliefs can count as delusions. We argue that delusions are complexes of higher and lower order attitudes. They constitute a distinctive type of failure of self-knowledge and self-management. We describe the relevant type. One of the conceptual implications of our view is that beliefs need not be central to delusions

Pedogenic Processes in Thick Sand Deposits on a Marine Terrace, Central California

Pedological studies in thick sedimentary sequences are generally limited to the upper few meters. Field investigation of thick (~50 m) sand deposits on an emergent Pleistocene marine terrace in central California showed morphological differences between the solum at the surface and the deep regolith. Based on morphological and geochemical features, four units were identified within the regolith. Two zones of active pedogenesis occur within three of these units. The surficial unit is in Holocene sand deposits (mixed, thermic, Argic Xeropsamments), and has darkened A horizons, a slightly reddened subsoil, and incipient lamellae at the depth of wetting front infiltration. These lamellae have slightly more day and Fe oxides than the soil above. Mineral weathering is intense at the surface. The other zone of active pedogenesis is at the base of the regolith, where a lithologic discontinuity above the terrace platform forms an aquitard, and throughflow occurs. Meteoric water percolates through thin regolith deposits above the shoreline angle, and at other locations on the terrace where sediment has been removed by erosion. Percolating water carries clay, organic matter, and solutes to the water table. Weathering is intense within this basal unit. Illuviation of clays and Fe oxides, and precipitation of Fe oxides and silica occur within this unit. As pore space is filled, fractures and channels become paths for saturated water flow. Eluviation of Fe occurs at these sites. Most of the intervening regolith is isolated from current pedogenesis by its great depth and a relatively dry Holocene climate. Well-developed lamellae are preserved as relicts of Pleistocene episodes of soil formation. These lamellae formed by illuviation of clay and Fe oxides, and were sites of silica precipitation. The conceptual model presented here is intended to facilitate understanding of pedogenic and geomorphological evolution of marine terrace deposits, and to assist with the interpretation of groundwater flow in these terrace systems

The Mystery Club: On Track with Tractor Safety

Farm safety newsletter and activities for youth, focusing on tractor safety, brought to you by Captain Overalls, the safety crusader.https://lib.dr.iastate.edu/extension_ag_pubs/1070/thumbnail.jp