Jurnal Online STTKD (Sekolah Tinggi Teknologi Kedirgantaraan)
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STUDI KEKUATAN TARIK KOMPOSIT SERAT JERAMI PADI YANG DIBUAT DENGAN METODE VACUUM BAGGING
No full textThis study aims to determine the effect of rice straw fiber orientation on the tensile strength of composite materials manufactured using the vacuum bagging method. The composites were made using rice straw fibers arranged in two orientations: parallel and random, with epoxy resin as the matrix. Specimens were produced according to ASTM D638 Type 1 standards and tested using a tensile testing machine. The results revealed that fiber orientation significantly influences tensile strength. The parallel fiber specimens achieved an average tensile strength. The parallel fiber specimens achieved an average tensile strength of 22.54 Mpa, significantly higher than the random fiber specimens which only reached 1.68 Mpa. The tensile strength difference between the two orientations was 20.86 Mpa. The tensile strength difference between the two orientations was 20.86 Mpa. It can be concluded that parallel fiber alignment provides better mechanical performance, making it more suitable for structural applications that require high tensile strength
Reverse-Engineering Speech and Music Categorization from a Single Sound Source
No full textClassifying whether an auditory signal is music or speech is important for both humans and computational systems. Although previous literature suggests that music and speech are easily separable categories, common experimental approaches may bias findings toward this distinction by relying on stimuli from different sound sources and predefined response labels. Here, we use stimulus material from the dùndún drum–a speech surrogate that can signal either speech-related or musical content. We first replicate standard speech-music categorization results (N=108). Then, we depart from the typical experimental procedure by asking new participants (N=180) to sort and label the stimulus material, without predefined categories. Hierarchical clustering of participants’ stimulus groupings reveals multiple organizing dimensions, with the speech–music distinction reliably present but secondary under label-free conditions. By reverse-engineering the relationship between sorting behavior, acoustic features, and semantic labels, we characterize how speech–music categorization relates to other salient perceptual dimensions and how its behavioral prominence depends on task constraints
Correction of saccadic decisions during active visual search in the monkey
No full textPrior research has shown that during tasks with very salient saccadic targets, like popout visual-search and double-step saccade tasks in both humans and monkeys, two-saccade sequences occur, where an initial saccade to a distractor is followed soon after by an ultra-short-latency (USL) second saccade to the popout target. This indicates that the USL second saccade uses visual information obtained before the first saccade and corrects the erroneous decision to make the first saccade to the distractor. Here, we demonstrate that such USL second saccades also often occur when monkeys perform active visual search without a popout visual target. Unlike in prior studies where the search target was extremely salient and therefore all second saccades showed a high accuracy towards the target, in our task, we show that USL saccades are preferentially directed towards the search-target and the transfer of target selection and location information across the first saccade is very accurate. USL saccades foveate the target more often than regular-latency saccades especially when the saccade starts far away from the target. We demonstrate various properties of USL saccades that reveal how the error-correction process is very accurate and how concurrent processing of saccade goals may proceed on the basis of computations in visual/oculomotor priority maps. Our results expand our understanding of saccadic targeting and information transfer across saccades during goal-directed active vision, lay the ground for future neurophysiological studies, and suggest that error-processing in different sensory and response modalities show similar patterns and may be accounted for by similar models
Emotional Variability and Educator Wellbeing: Evidence from a Semester-Long Study
No full textRecent research suggests that experiencing positive emotions is related to overall wellbeing, and thus, school systems should employ strategies to boost educators’ experiences of positive emotions for improved wellbeing. However, most of these studies captured one-time measures linking positive emotions to educator wellbeing, meaning the field lacks knowledge about how fluctuating emotions relate to educator wellbeing over time. This study utilized panel data to examine how 40 U.S. K–12 educators’ extent of positive emotions related to their reported wellbeing across the spring 2022 semester and how educators’ professional characteristics interacted with their emotional experiences to predict wellbeing. Results indicated that the experience of no positive emotions was negatively related to educator wellbeing, while experiencing even some positive emotions predicted substantively higher levels of reported wellbeing over the course of a semester. Classroom teachers, elementary and middle school educators, and less experienced educators were more vulnerable to lower levels of wellbeing when they experienced no positive emotions
Rights for Those Who Unwillingly, Unknowingly and Unidentifiably Compute!
No full textFinal published version: Michael Veale, ‘Rights for Those Who Unwillingly, Unknowingly and Unidentifiably Compute!’ in Hans-W Micklitz and Giuseppe Vettori (eds), The Future of the Person (Hart Publishing 2025) 231-254 https://doi.org/10.5040/9781509982752.ch-013
Abstract Profiling of individuals has long been a concern to scholars and civil society, and a lucrative way for platforms to shape markets and extract value. However, people and their environments are not just computed, but they are increasingly also expected to become agents in large scale computations. The strengthening of privacy and data protection law has been used as a reason to move more and more advanced computation concerning individuals, groups and environments onto people’s devices, in a shift called ‘local processing’. This sees individuals’ devices and software work together to undertake collective computations, which often claim to be confidential with regard to the data of each person involved. For example, using technologies such as secure multi-party computation, phones may work together to create models or analysis of spoken language, without revealing anything that any user said to any other person. Such privacy-enhancing technologies equate privacy with confidentiality, and have interesting potential, but seeing an individual as participants in a computation raises new challenges. What autonomy do people have to shape such participation, given the limited technical and practical control over the devices in their pockets? Does their contribution to ethically questionable computation bring some responsibility, and should they be facilitated to refuse to participate in it? How does the individual relate to the overarching forces that orchestrate their ‘personal’ computers? Here, I present a guide and an agenda to navigate these issues, and analyse emerging regimes, such as the ex ante provisions in the Digital Markets Act and the Data Act, as well as interpretations of the General Data Protection Regulation, to understand how, if at all, they support those that unwillingly, unknowingly and perhaps even unidentifiably facilitate, rather than become the subject of, controversial computation
Discovering the unknown unknowns of research cartography with high-throughput natural description
No full textTo succeed, we posit that research cartography will require high-throughput natural description to identify unknown unknowns in a particular design space. High-throughput natural description, the systematic collection and annotation of representative corpora of real-world stimuli, faces logistical challenges, but these can be overcome by solutions that are deployed in the later stages of integrative experimental design
Continuity as a characteristic of revolutions: an essay in comparative history
No full textThis is an essay on comparative constitutional history and comparative revolution. In it, I will consider the development of the rule of law as a phase of state building, paying particular attention to representative institutions. I will compare the constitutional histories of England, France, Russia, Germany and the United States from their origins to the point in each nation’s history which I consider the end of that country’s revolution. It is my thesis that all revolutions are about law and constitutional arrangement and that continuity is a characteristic of the political and constitutional arrangements which exist before and after revolutions. Revolutions answer the question: Who makes law? Where in the state does the legislative authority reside? I hope to show that the outcome of a revolution, the constitutional arrangements that result from it, is largely determined by the system of government that existed before the revolution. That is, however much revolutionaries might want to make a clean break with the past and create a totally new political system, the ultimate revolutionary outcome will have some continuity with the prerevolutionary system
Qualitative Constraints on Models of Eyewitness Identification
No full textTheoretical accounts of eyewitness identification differ fundamentally in their assumptions about memory representation and decision processes, yet competing models can often be adjusted to fit the same aggregate identification data. This underdetermination has limited the ability of standard model-comparison approaches to adjudicate between discrete-state threshold models and continuous-strength models derived from signal detection theory. We adopt a constraint-based approach that evaluates whether eyewitness identification data satisfy qualitative predictions that must hold under specific classes of models, independent of parameter values or overall goodness of fit. Using forced-choice and rank-ordering data from lineups of varying sizes, we test two necessary assumptions underlying discrete-state threshold representations: that identification decisions admit a stochastic latent-strength representation, and that rank-conditional hazard functions increase monotonically under the double high-threshold (2HT) model. Forced-choice performance across lineup sizes satisfies the qualitative constraints required for a stochastic latent-strength representation with monotonic likelihood, supporting the treatment of identification responses as ordered by strength. In contrast, rank-ordered identification data exhibit systematic non-monotonicity in target hazard functions beyond the first-ranked choice, violating a structural prediction of the 2HT model that is independent of auxiliary assumptions. These findings rule out the 2HT model, and related discrete-state threshold accounts, as viable representations of eyewitness identification under monotonic strength-ordering assumptions and illustrate how exploiting task structure and qualitative constraints can provide decisive tests of cognitive architectures in domains where fit-based model comparisons have proven inconclusive
