Temporal Boundary Research Articles

Video-based Soft Tissue Deformation Tracking for Laparoscopic Augmented Reality-based Navigation in Kidney Surgery.

Minimally invasive surgery (MIS) remains technically demanding due to the difficulty of tracking hidden critical structures within the moving anatomy of the patient. In this study, we propose a soft tissue deformation tracking augmented reality (AR) navigation pipeline for laparoscopic surgery of the kidneys. The proposed navigation pipeline addresses two main sub-problems: the initial registration and deformation tracking. Our method utilizes preoperative MR or CT data and binocular laparoscopes without any additional interventional hardware. The initial registration is resolved through a probabilistic rigid registration algorithm and elastic compensation based on dense point cloud reconstruction. For deformation tracking, the sparse feature point displacement vector field continuously provides temporal boundary conditions for the biomechanical model. To enhance the accuracy of the displacement vector field, a novel feature points selection strategy based on deep learning is proposed. Moreover, an ex-vivo experimental method for internal structures error assessment is presented. The ex-vivo experiments indicate an external surface reprojection error of 4.07 ± 2.17mm and a maximum mean absolutely error for internal structures of 2.98mm. In-vivo experiments indicate mean absolutely error of 3.28 ± 0.40mm and 1.90±0.24mm, respectively. The combined qualitative and quantitative findings indicated the potential of our AR-assisted navigation system in improving the clinical application of laparoscopic kidney surgery.

İZMİR EFRENC GÜMRÜĞÜ’NÜN BİR AYLIK HASILATININ MÜBEYYİN İCMAL DEFTERİNİN TRANSKRİPSİYONU

Throughout history, it is known that the Ottoman Empire had commercial relations with other
 states. It is possible to access customs records from the provide information about these relations
 and the maintained ledgers. However, studies focusing on transcription and analysis in the field of
 accounting history are limited. In this regard, the Presidency of Republic of Türkiye Directorate of
 State Archives (PMOA) transcription of brief ledger number ML.VRD.d, encoded as 867, belonging
 to Izmir Efrenç Customs, obtained from the Prime Ministry Ottoman Archives, was conducted in the
 study, and inferences were made. The transcription of the document was limited to the period from 13
 Rabiu’l-ahir 1259 (May 13, 1843) to 14 Cemaziye’l evvel 1259 (June 12, 1843), serving as the temporal
 boundary for the study. The purpose of the study was to contribute to individuals conducting
 research on accounting history by examining the accounting records in the brief ledger of Izmir Efrenç
 Customs. The results of the study, revealed that the records were related to the fundamental concepts
 of accounting, including complete explanations and expressions in terms of monetary values, and the
 total customs revenue amounted to 136,367.5 Guruş and 19 Akçe.

Choice of metrics matters—Future scenarios on milk and beef production in Norway using an LCA approach

The consumption of dairy and beef products is expected to increase globally in the future, and at the same time, food must be produced in a more sustainable way, including reduced greenhouse gas (GHG) emissions, avoided feed-food competition, and reduced biodiversity loss. The purpose of the study was to a) provide an overall life cycle assessment (LCA) of these impacts for various future milk and beef production systems in Norway and b) determine how the choice of metrics for climate change affects the results. System boundaries were from cradle to farm gate and the temporal boundary was 2017 with future scenarios for 2040. The actual production and consumption in Norway in 2017 was used as a baseline (BL), and the sustainability of future Norwegian domestic production of milk and beef was assessed through three scenarios for 2040: 1) a trend yield scenario (TrendY) based on an expected increase in milk yield following the present trend, 2) a high yield scenario (HighY) with higher increase in the milk yield per cow per year than the trend, and 3) a low yield scenario (LowY) where the milk yield per cow per year was adjusted for covering the domestic demand for beef solely from dual-purpose production and no domestic specialized beef production. The beef production per dual-purpose cow was kept constant and the remaining domestic demand in scenario 1 and 2 were covered by specialized beef production. Climate change was assessed using both a GWP100 and a GWP* approach. The HighY scenario had the lowest impact on climate change using GWP100, but when taking the different behaviors of short- and long-term climate pollutants into account (GWP*), the ranking of the future scenarios changed and favored LowY. The potential biodiversity loss was lower for the LowY scenario because the proportion of concentrates in the dairy cow ration was decreased due to lower milk yield. Similarly, the feed-food competition was lower (land use ratio < 1) for the LowY. The results of our study suggest that the choice of metric for GWP and time frame highly affects the results and conclusions and strategies for climate smart and sustainable livestock production should therefore be made with caution.

Reflection and refraction of a super-Gaussian optical pulse at a moving temporal boundary

We investigate the transmission properties of super-Gaussian pulses at a moving temporal boundary. The incident spectrum of super-Gaussian pulses, determined by different shape parameters, affects the reflected and transmitted pulse energy and the sidelobes distribution after crossing the temporal boundary. When the incident pulse is an initial unchirped super-Gaussian pulse or a super-Gaussian pulse with a small chirp parameter, the reflected pulse energy increases and the transmitted pulse energy decreases as the incident pulse shape parameter increases. When the incident pulse with a initial chirp and |C|≥2, the incident pulse spectrum mainlobe energy increases as the shape parameter increases, resulting in reflected pulse energy decreases and transmitted pulse energy increases. This study also discusses the pulse splitting occurs in the anomalous dispersion region. The super-Gaussian pulse sidelobes can theoretically be removed by creating two temporal boundaries.

Flowsheet design and environmental impacts of cobalt co-product recovery from complex Au-Co ores

The increasing demand for battery metals, such as cobalt, increases the attractiveness of conventionally overlooked raw materials, such as small multi-metal deposits. With the length of mining and extractive metallurgy projects, it is advantageous to evaluate possible processing routes well in advance with a variety of tools, such as experimental, piloting, simulation, and life cycle assessment. In this study, simulation-based life cycle assessment was used to compare the baseline of only recovering gold from sulfidic Au-Co-(Cu-As) ores to five scenarios where both gold and cobalt were recovered, the latter as battery grade cobalt sulfate heptahydrate. Technical performance and several impact categories affecting climate change, ecosystems, and human health, were investigated to assess the advantages and drawbacks of each option.The environmental competitiveness varied between different studied scenarios vs. observed impact categories. The baseline process - with no cobalt recovery - had the lowest energy and global warming impacts but fared worse in toxicity categories. Pressure leaching scenario achieved low toxicities but was shown to be environmentally highly intensive in all other categories. The pyrometallurgical-hydrometallurgical roasting-leaching process resulted in the lowest environmental impacts in most of the studied categories. However, in terms of acidification and photochemical oxidant creation, the fine grinding-leaching process was the best option. In all studied scenarios the major technical challenge was found to be the stabilization of arsenic, yet the technical issues can effectively be resolved by treating the arsenical and non-arsenical concentrates in separate processes. In the current results, the temporal boundary, allocation choice, and current lack of experimental work remain major sources of uncertainty.

Energy Cascade Phenomena in Temporal Boundary Layers

Energy Cascade Phenomena in Temporal Boundary Layers

Operations, IT, and construction time orientations and the challenges of implementing IOT

The adoption of Internet of Things has grown significantly in recent years both to address sustainability in campus operations and as part of digital twin systems. This study looks at in-depth cases of large university campus owners and the challenges that this IOT introduces for the maintenance and management of these systems and the data they collect. In this ethnography there are three main time orientations related to facilities management (Facilities), Information Technology (IT), and Capital Projects. First, a university campus is like a small city, with buildings, utilities, and transportation systems - taken together we call this campus infrastructure (buildings 50-100, roads and utilities 20-50 years). Second, IT employees think on 2–3-month scale, working through implementing software and hardware upgrades, configurations and patches, at times needing agile operations to deal with emerging cybersecurity threats. Third, in Capital Projects the design phase can last 9 months, and the construction from 1 - 2 years for a typical project, and this is where IOT technologies are often first introduced into campus. While the capital project teams reflect on the user experience, these teams are often removed from the realities of facilities management and do not understand the time scales or the scope of the work that is required to manage a portfolio of Facilities and IT systems. In this paper, we explore how these time orientations lead to tensions in the owners’ selection of IOT devices and systems, in the integration of new technologies into existing systems, and in the operations of keeping existing systems up and running for the longer time scales of campus infrastructure life spans. Furthermore, this paper presents a paradox: If they speed up, they lose things, if they slow down, they lose other things, and presents ways that owner organizations manage this paradox through temporal boundary spanners who understand the disciplinary requirements, cultures, and frameworks across the organization and helps to mitigate the tensions across these differences.

Taxic and morphological diversification during the early radiation of Clupeomorpha (Actinopterygii, Teleostei)

AbstractEvolutionary radiation is a problematic concept whose definition and classification have recently changed. Radiations can be defined as the pattern of abrupt increase in diversity of a lineage. It is relevant to evaluate the presence and interaction of different types of radiation in extant and fossil organisms to adequately delimitate the radiation types and to know the diversity in the context of Earth's history. Here, we employed the superorder Clupeomorpha at the Early–Late Cretaceous boundary as a study case to investigate radiation types and their interactions, using both taxic and morphological approaches. Clupeomorpha is an extensively studied, diverse and ancient teleostean superorder with wide geographical and ecological distributions. We propose a model for calculating rates of origination in order to analyse the taxic diversification and employ geometric morphometrics to analyse the morphological diversification that occurred at the temporal boundary. The results suggest the absence of taxic radiation due to a constant increase in taxon origination. However, the expansion of the phylomorphospace occupation and the disparity increase suggest the presence of a ‘climatic–geographical’ or ‘broad diversification‐like’ disparity, according to current classifications. This illustrates the incompatibility of current radiation classifications with this case study.

Investigation of thermodynamic properties in picosecond laser-produced plasmas on silicon

The validity of local thermodynamic equilibrium (LTE) in plasma is a long-term concern for laser-induced breakdown spectroscopy applications. In this paper, the spatial and temporal dependence of LTE deviation in picosecond laser-induced plasmas has been proved. A picosecond (∼20 ps) laser operated at 532 nm was used to ablate a silicon target to produce plasma at a pressure of 10−5 mbar. A general electron energy distribution function was used to provide access to the insight into population ratios of different energy levels for the spatially and temporally resolved optical emission intensity of laser-induced plasma. A precise temporal and spatial LTE boundary of plasma generated in picosecond laser ablation was obtained, and the results showed that only at delay times of 180–300 ns, the plasma away from the surface (&amp;gt;4 mm) is in LTE.

Optical analogy for temporal diffraction in tight-binding lattice.

The wave propagating through the temporal boundary has attracted considerable attention in the past few years because of the potential applications of time-varying systems in the optics community. However, temporal diffraction of light remains to be investigated, because free space is non-dispersive. Here, we theoretically provide the analytical expressions for the temporal diffraction contributions of electron waves across the temporal boundary between the free space and a dispersive medium. With the help of coupled waveguide arrays, temporal diffraction is analogously observed by the optical platform. The optical analogy results confirm the theoretical predictions of the temporal diffraction wave at the temporal boundary. By changing the permittivity of the waveguides, implying the coupling coefficient is modified, the temporal diffraction angle is tuned. Our analysis and observations of temporal diffraction of dispersive media have great potential in time-varying physics, signal processing, and photonics communications.

Quantum Antireflection Temporal Coatings: Quantum State Frequency Shifting and Inhibited Thermal Noise Amplification

AbstractThe quantum optical response of antireflection temporal coatings (ATCs), that is, matching temporal layers that suppress the generation of backward waves in temporal boundaries, is investigated. The results reveal that quantum ATCs are characterized for inducing a frequency shift of the quantum state, while preserving all photon statistics intact. Thus, they can find application for fast quantum frequency shifting in photonic quantum networks. The quantum theory also provides additional insight on their classical mode of operation, clarifying which quantities are preserved through the temporal boundary. Last, it is shown that quantum ATCs allow for fast temporal switching without amplification of thermal fields.

Emergence of Meaning Amidst a Tension Between Forms and Contents.

In this paper, I propose an analysis of the tension between forms and contents as a condition of emergence of meaning. I refer to Vygotsky's earlier work "Psychology of Art" as an inspiration, to develop my own model. This leads me to present an analysis of how forms overcome contents in a monological way, but also in a dialogical perspective. I also present two windows of emergence capturing the dynamics occurring in the temporal boundary before the stabilization of a new form (what happens between the form deconstruction and the emergence of a new form). I apply it to how elders experienced the pandemic and its aftermath, using the analysis of discourse of elders participating in a group-intervention and in an action-research project. This enables me to partially respond to some of the challenges identified by Greve (2023, this Special Issue) -an author I was asked to comment-, but also to go beyond his propositions.

Less is More: Surgical Phase Recognition from Timestamp Supervision.

Surgical phase recognition is a fundamental task in computer-assisted surgery systems. Most existing works are under the supervision of expensive and time-consuming full annotations, which require the surgeons to repeat watching videos to find the precise start and end time for a surgical phase. In this paper, we introduce timestamp supervision for surgical phase recognition to train the models with timestamp annotations, where the surgeons are asked to identify only a single timestamp within the temporal boundary of a phase. This annotation can significantly reduce the manual annotation cost compared to the full annotations. To make full use of such timestamp supervisions, we propose a novel method called uncertainty-aware temporal diffusion (UATD) to generate trustworthy pseudo labels for training. Our proposed UATD is motivated by the property of surgical videos, i.e., the phases are long events consisting of consecutive frames. To be specific, UATD diffuses the single labelled timestamp to its corresponding high confident ( i.e., low uncertainty) neighbour frames in an iterative way. Our study uncovers unique insights of surgical phase recognition with timestamp supervision: 1) timestamp annotation can reduce 74% annotation time compared with the full annotation, and surgeons tend to annotate those timestamps near the middle of phases; 2) extensive experiments demonstrate that our method can achieve competitive results compared with full supervision methods, while reducing manual annotation costs; 3) less is more in surgical phase recognition, i.e., less but discriminative pseudo labels outperform full but containing ambiguous frames; 4) the proposed UATD can be used as a plug-and-play method to clean ambiguous labels near boundaries between phases, and improve the performance of the current surgical phase recognition methods. Code and annotations obtained from surgeons are available at https://github.com/xmed-lab/ TimeStamp-Surgical.

Tutorial on the conservation of momentum in photonic time-varying media [Invited

Time-varying media break temporal symmetries while preserving spatial symmetries intact. Thus, it represents an excellent conceptual framework to investigate the fundamental implications of Noether’s theorem for the electromagnetic field. At the same time, addressing momentum conservation in time-varying media sheds light on the Abraham-Minkowski debate, where two opposing forms of the electromagnetic field momentum are defended. Here, we present a tutorial review on the conservation of momentum in time-varying media. We demonstrate that the Minkowski momentum is a conserved quantity with three independent approaches of increasing complexity: (i) via the application of the boundary conditions for Maxwell equations at a temporal boundary, (ii) testing for constants of motion and deriving conservation laws, and (iii) applying temporal and spatial translations within the framework of the Lagrangian theory of the electromagnetic field. Each approach provides a different and complementary insight into the problem.

Convergence rates in homogenization of parabolic systems with locally periodic coefficients

In this paper we study the quantitative homogenization of second-order parabolic systems with locally periodic (in both space and time) coefficients. The O(ε) scale-invariant error estimate in L2(0,T;L2dd−1(Ω)) is established in C1,1 cylinders under minimum smoothness conditions on the coefficients. This process relies on critical estimates of smoothing operators. We also develop a new construction of flux correctors in the parabolic manner and a sharp estimate for temporal boundary layers.

Temporal negative refraction [Invited

Negative refraction is a peculiar wave propagation phenomenon that occurs when a wave crosses a boundary between a regular medium and a medium with both constitutive parameters negative at the given frequency. The phase and group velocities of the transmitted wave then turn anti-parallel. Here we propose a temporal analogue of the negative refraction phenomenon using time-dependent media. Instead of transmitting the wave through a spatial boundary, we transmit it through an artificial temporal boundary created by switching both parameters from constant to dispersive with frequency. We show that the resulting dynamics are sharply different from the spatial case, featuring both reflection and refraction in positive and negative regimes simultaneously. We demonstrate our results analytically and numerically using an electromagnetic medium. In addition, we show that by targeted dispersion tuning, the temporal boundary can be made nonreflecting while preserving both positive and negative refraction.

Drill-Rep: Repetition counting for automatic shot hole depth recognition based on combined deep learning-based model

In order to solve the problems of low efficiency and dependability of human experience in shot hole depth recognition by manual interpretation of the massive drilling videos, this paper proposed a repetition counting framework from the perspective of representation object motion, and firstly studied and realized the automatic shot hole depth recognition by adopting the proposed framework by combining multiple deep learning-based models. Firstly, the periodic motion characteristics of the objects in the drilling video were analyzed, and the motion extraction model of the representative object was established based on YOLOv5 and Deep SORT algorithm to obtain the spatiotemporal sequence. Then, the sequence noise and redundant information were filtered according to the spatiotemporal relationship between the drill pipes and workers, to obtain a coherent, smooth, and clean motion sequence. On this basis, a drill pipe motion counting model was established by using the YOLOv5 network to detect the temporal boundary and repetition number of the drill pipe motion. Finally, combined with the pipe motion extraction model and counting model, the comprehensive reliable recognition method of shot hole depth was presented. The shot hole depth recognition trial was carried out on 1029 drilling videos from the Bureau of Geophysical Prospecting INC. The proposed method achieved 90.5% recognition accuracy (Acc) and 0.027 mean absolute error (MAE) with 64 frames per second (FPS) and 0.39 average recognition time ratio (Rt). Therefore, the proposed repetition counting framework solved the problem of efficient and intelligent drilling depth recognition of massive drilling videos and thus provided a new idea for repetition counting.

Active learning with effective scoring functions for semi-supervised temporal action localization

Temporal Action Localization (TAL) aims to predict both action category and temporal boundary of action instances in untrimmed videos, i.e., start and end time. Existing works usually adopt fully-supervised solutions, however, one of the practical bottlenecks in these solutions is the large amount of labeled training data required. To reduce expensive human label cost, this paper focuses on a rarely investigated yet practical task named semi-supervised TAL and proposes an effective active learning method, named AL-STAL. We leverage four steps for actively selecting video samples with high informativeness and training the localization model, named Train, Query, Annotate, Append. Two scoring functions that consider the uncertainty of localization model are equipped in AL-STAL, thus facilitating the video sample ranking and selection. One takes entropy of predicted label distribution as measure of uncertainty, named Temporal Proposal Entropy (TPE). And the other introduces a new metric based on mutual information between adjacent action proposals, named Temporal Context Inconsistency (TCI). To validate the effectiveness of proposed method, we conduct extensive experiments on three benchmark datasets THUMOS’14, ActivityNet 1.3 and ActivityNet 1.2. Experiment results show that AL-STAL outperforms the existing competitors and achieves satisfying performance compared with fully-supervised learning.

Deep Learning-Based Action Detection in Untrimmed Videos: A Survey.

Understanding human behavior and activity facilitates advancement of numerous real-world applications, and is critical for video analysis. Despite the progress of action recognition algorithms in trimmed videos, the majority of real-world videos are lengthy and untrimmed with sparse segments of interest. The task of temporal activity detection in untrimmed videos aims to localize the temporal boundary of actions and classify the action categories. Temporal activity detection task has been investigated in full and limited supervision settings depending on the availability of action annotations. This article provides an extensive overview of deep learning-based algorithms to tackle temporal action detection in untrimmed videos with different supervision levels including fully-supervised, weakly-supervised, unsupervised, self-supervised, and semi-supervised. In addition, this article reviews advances in spatio-temporal action detection where actions are localized in both temporal and spatial dimensions. Action detection in online setting is also reviewed where the goal is to detect actions in each frame without considering any future context in a live video stream. Moreover, the commonly used action detection benchmark datasets and evaluation metrics are described, and the performance of the state-of-the-art methods are compared. Finally, real-world applications of temporal action detection in untrimmed videos and a set of future directions are discussed.

Unraveling the sustainability aspects of coal extraction and use in Bangladesh using material flow analysis and life cycle assessment

Bangladesh's metamorphosis into an export-based industrial economy from an agrarian one pushes its grid energy mix to lean towards a coal-dominated future which contradicts its Sustainable Development Goals (SDG) aspirations. Bangladesh needs local Life Cycle Inventory (LCI) databases to assist informed high-impact policymaking since product and process sustainability assessments are becoming inevitable for compliances. Bangladesh lacks an LCI database for coal mining and import which this study aimed to prepare. Besides, this study conducted both Material Flow Analysis (MFA) and Life Cycle Assessment (LCA) of coal to elucidate options for making imports and utilizations of coal more sustainable. The functional unit of the LCA was 1-MT (metric ton) energetic hard coal, the spatial system boundary was the international border of Bangladesh, and the temporal system boundary was the 2017 fiscal year. LCA used ILCD and ReCiPe 2006 impact assessment methods. The study used both primary and secondary data on mining, import, transportation, and sectoral use of coal. Overall, the environmental impacts of imported coal were higher than locally mined coal if the mining process at the source is considered. Coal consumption in Bangladesh mainly contributed to - Climate change (835 kg CO2 eq), causing 22% of the total environmental burden, followed by Human toxicity, cancer effects (18%); Acidification (16%); Human toxicity, non-cancer effects (13%) midpoint indicators. Coal sourcing scenario analysis indicated importing coal from Australia, South Africa, and Indonesia is the lower-impact options than importing from India. Surprisingly, MFA indicated 46% of the total input as hidden import flows, indicating the need for intensive investigation to evaluate hidden flows. MFA also indicated the need to reduce the reliance of brick kilns on coal besides assuring the cleanest coal-fired power plants. The results produced the baseline of impacts for mining, importing and using coal in Bangladesh as the country is poised to see a rapid increase in coal import, extraction and use. The hotspot analysis indicated options for coal mine management in Bangladesh to lower the environmental footprint of mining.