434 research outputs found
How Trustworthy are the Existing Performance Evaluations for Basic Vision Tasks?
This paper examines performance evaluation criteria for basic vision tasks
involving sets of objects namely, object detection, instance-level segmentation
and multi-object tracking. The rankings of algorithms by current criteria
fluctuate with different choices of parameters, e.g. Intersection over Union
(IoU) threshold, making their evaluations unreliable. More importantly, there
is no means to even verify whether we can trust the evaluations of a criterion.
This work advocates a notion of trustworthiness for criteria, which requires
(i) robustness to parameters for reliability, (ii) contextual meaningfulness in
sanity tests, and (iii) consistency with mathematical requirements such as the
metric properties. We show that such requirements were overlooked by many
widely-used criteria. We also explore alternative criteria using metrics for
sets of shapes, and assess them against these requirements to find trustworthy
criteria
Multi-Objective Multi-Agent Planning for Jointly Discovering and Tracking Mobile Object
We consider the challenging problem of online planning for a team of agents
to autonomously search and track a time-varying number of mobile objects under
the practical constraint of detection range limited onboard sensors. A standard
POMDP with a value function that either encourages discovery or accurate
tracking of mobile objects is inadequate to simultaneously meet the conflicting
goals of searching for undiscovered mobile objects whilst keeping track of
discovered objects. The planning problem is further complicated by
misdetections or false detections of objects caused by range limited sensors
and noise inherent to sensor measurements. We formulate a novel multi-objective
POMDP based on information theoretic criteria, and an online multi-object
tracking filter for the problem. Since controlling multi-agent is a well known
combinatorial optimization problem, assigning control actions to agents
necessitates a greedy algorithm. We prove that our proposed multi-objective
value function is a monotone submodular set function; consequently, the greedy
algorithm can achieve a (1-1/e) approximation for maximizing the submodular
multi-objective function.Comment: Accepted for publication to the Thirty-Fourth AAAI Conference on
Artificial Intelligence (AAAI-20). Added algorithm 1, background on MPOMDP
and OSP
Development of risk management framework for the construction industry in yemen
Yemen is one of the developing poorest economies in the world, yet it has seen extraordinary growth in construction over the last few decades. The construction sector is considered an important sector in developing economies and contributes significantly to the improvement of the economic growth of any country, particularly in developing countries like Yemen. Construction projects regularly experience a high level of uncertainty due to its Complexity, which definitely exposes them to risks that result a negative impact on the project's objectives. Given developing countries' resource constraints compared to developed countries, it is critical to accomplish construction projects on schedule, within budget, and with the highest possible quality. Thus, risk management is a critical component of the construction industry's decision-making process, as it determines the success or failure of construction projects. The absence of application and understanding of risk management leads to poor construction project performance particularly in developing countries. Risk management in construction projects in Yemen is under-researched compared to developed and developing countries, and lacking a suitable risk management framework. Hence, the main objective of this research is to develop a risk management framework in order to improve the performance of construction projects in Yemen. In order to achieve the research objectives, a mixed-method approach was used, which included semi-structured interviews and questionnaires with participants in a construction project in Yemen. Through an extensive literature review, 56 risk factors affecting construction projects in developing countries from43 studies were identified and categorized. Semi-structured interviews with construction experts in Yemen were conducted and 48 risk factors related to the Yemeni construction projects have been identified. A questionnaire survey utilizing a nonprobability sampling method using a five-point scale was carried out among the construction sector in Yemen to identify the most significant risk factors based on the likelihood of occurrence and impact on the objectives of projects, and to evaluate the current practice and knowledge of risk management in construction projects in Yemen,. 174 responses were completed and collected from the public and private sectors. 17 critical risks were identified using the mean, the relative important index method, and risk acceptability matrix analysis. War and political instability, inflation, and exchange rate fluctuations are identified as the most significant risks. Most of the risks are allocated to the contractor or shared between owner and contractor. The current knowledge and practice of the construction projects in Yemen have been evaluated. The results also show that risk management is not implemented in most projects, the majority of participants in construction don’t have adequate knowledge of risk management, and risk management does not apply systematically in construction projects. Based on the findings from the literature reviews, and data analysis a risk management framework has been developed to be served as a guideline for managing risks in construction projects in Yemen and developing countries. The framework was developed based on the principles including developing the existing frameworks; utilizing risk management tools that have been implemented successfully in other countries. The framework has provided incorporated techniques for risk management that is based on well-defined principles. The developed framework has validated using a semi-structured interview with 16 Yemeni construction experts. Experts’ feedback demonstrates that the developed framework is comprehensive and compatible with the Yemen environment, and does not involve complicated processes. This study will serve as a guideline for participants in construction projects in Yemen to improve the performance of construction projects
Cultural, morphological, pathogenic and molecular characterization of Alternaria mali associated with Alternaria leaf blotch of apple
Alternaria blotch (Alternaria mali) causes severe foliar damage to apple trees in Kashmir. Twenty one (21) isolates of A. mali were collected from different locations and characterized for cultural, morphological, pathogenic and molecular variations. A. mali colonies varied in their cultural behaviour ranging from velvety to cottony, mostly appressed, with regular to irregular margins. Colour of colonies ranged between light to dark olivacious. Isolates impregnated media with colour ranging between grey to brown. Growth rate of isolates was between 5.86 to 8.21 mm/day with fast growth in isolate Am-13 and least in Am-5. Morphological variations in size, shape and septation of hyphae, conidiophore and conidia were observed in the isolates with significant variations in conidiophore and conidial septation. Average conidial size ranged from 21.36 to 31.74 x 8.34 to 14.48 μm. Isolates exhibited variations in incubation period, number and size of the lesions were produced. The dendrogram analysis, based on cultural, morphological and pathogenic studies, revealed variation within A. mali population. At 67% similarity matrix, all the isolates formed 2 clusters with 12 and nine isolates in cluster I and II, respectively. However, dendrogram on molecular (random amplification of polymorphic DNA, RAPD) basis revealed five clusters at 68% Dice similarity coefficient. There was no congruence between RAPD pattern and cultural, morphological and pathogenic characters. Isolates identical for one spectrum were often dissimilar for other spectrum. The results demonstrate existence of considerable variation in cultural, morphological, pathogenic and molecular characters of A. mali isolates prevalent in Kashmir valley.Keywords: Apple, Alternaria mali, variability, cultural, morphological, pathogenic, RAPDAfrican Journal of Biotechnology Vol. 12(4), pp. 370-38
An assistive robotic hand based on human computer interface (HCI) and shape memory alloy (SMA) actuator
Rehabilitation and assistive robotics is an emerging field of research where researchers are trying to develop
tailored made robotic devices to address the challenge of disability. This paper presents a study on feedback
controlled wearable robotic hand for grasping. The proposed design is compact and sufficiently light to be
used as an assistive hand. It is tendon driven and jointless
structure that has the potential to be used as an
assistive device for stroke patients. The concept has been implemented for index and thumb fingers as a first
prototype to enable grasping. Shape memory alloy (SMA) actuator and bias force mechanism are used for the
purpose of hand’s flexion and extension. This paper describes the mechatronic design of the wearable hand,
simulation, modeling, and development of the actuation unit and sensory system. Experiments of open loop
controller were conducted to understand the hand characterization and grip force provided by index finger. A
feedback controller (proportional controller) was implemented for this prototype with gripping force as the
feedback parameter. It was observed that approximately 2.25 A current caused 4 cm displacement for SMA
actuator. The maximum temperature of the SMA actuator was achieved to be 100 °C. The attainable gripping
force was around 2 N for a load free finger. The conducted experiments showed promising results that
encourages further development on this
Iranian midwives’ lived experiences of providing continuous midwife-led intrapartum care: a qualitative study
BACKGROUND & OBJECTIVE: Continuity of midwifery-led care during labour and birth is considered optimal. To ensure its sustainability in practice where limited evidence is available, the aim of the present study was to explore midwives’ lived experiences of delivering continuous midwife-led intrapartum care. METHODS: This study took a qualitative approach in meeting its aim. Participants were midwives working in the labour wards of private and public hospitals in Iran. The data were purposefully collected in 2019 through in-depth, semi-structured, and face-to-face interviews with midwives (n = 10) aged between 26 and 55 years. A thematic analysis based on descriptive phenomenology was undertaken to make sense of the data collected. RESULTS: “Wanting to lead continuous woman-centered care but being unable to” was identified as an overarching theme. Three other themes “emphasis on the non-interventional care”, “midwifery-specific focus” and “barriers and challenges of midwifery care” were also identified. Ultimately, midwives described knowing how to and wanting to lead continuous ‘woman’-centered care but being unable to. Perceived barriers included lack of familiarity with and knowledge in relation to childbirth, the insignificant role of midwives in decision making, obstetrician utilitarianism, high workloads along with work-related stress argument-driven communication between midwives and obstetricians and an absence of a ‘triangle of trust’ in care. CONCLUSION: Future research strategies could usefully include obstetricians and focus on the upscaling of midwifery in Iran using continuity of care models, highlight the value of midwives, identify why uptake of antenatal education in Iran is poor and develop user friendly, evidence based, midwife-led programs. Initiatives aiming to promote mutual professional respect, trust and collegiality and increased remuneration for midwifery work would be also welcomed in pursuit of reducing maternal and infant mortality in Iran
A multiple model probability hypothesis density tracker for time-lapse cell microscopy sequences
Abstract. Quantitative analysis of the dynamics of tiny cellular and subcellular structures in time-lapse cell microscopy sequences requires the development of a reliable multi-target tracking method capable of tracking numerous similar targets in the presence of high levels of noise, high target density, maneuvering motion patterns and intricate interactions. The linear Gaussian jump Markov system probability hypothesis density (LGJMS-PHD) filter is a recent Bayesian tracking filter that is well-suited for this task. However, the existing recursion equations for this filter do not consider a state-dependent transition probability matrix. As required in many biological applications, we propose a new closed-form recursion that incorporates this assumption and introduce a general framework for particle tracking using the proposed filter. We apply our scheme to multi-target tracking in total internal reflection fluorescence microscopy (TIRFM) sequences and evaluate the performance of our filter against the existing LGJMS-PHD and IMM-JPDA filters
Analogue peptides for the immunotherapy of human acute myeloid leukemia
Accepted manuscript. The final publication is available at: http://link.springer.com/article/10.1007%2Fs00262-015-1762-9The use of peptide vaccines, enhanced by adjuvants, has shown some efficacy in clinical trials. However, responses are often short-lived and rarely induce notable memory responses. The reason is that self-antigens have already been presented to the immune system as the tumor develops, leading to tolerance or some degree of host tumor cell destruction. To try to break tolerance against self-antigens, one of the methods employed has been to modify peptides at the anchor residues to enhance their ability to bind major histocompatibility complex molecules, extending their exposure to the T-cell receptor. These modified or analogue peptides have been investigated as stimulators of the immune system in patients with different cancers with variable but sometimes notable success. In this review we describe the background and recent developments in the use of analogue peptides for the immunotherapy of acute myeloid leukemia describing knowledge useful for the application of analogue peptide treatments for other malignancies
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