On asymptotic behaviors and convergence rates related to weak limiting distributions of geometric random sums

summary:Geometric random sums arise in various applied problems like physics, biology, economics, risk processes, stochastic finance, queuing theory, reliability models, regenerative models, etc. Their asymptotic behaviors with convergence rates become a big subject of interest. The main purpose of this paper is to study the asymptotic behaviors of normalized geometric random sums of independent and identically distributed random variables via Gnedenko's Transfer Theorem. Moreover, using the Zolotarev probability metric, the rates of convergence in some weak limit theorems for geometric random sums are estimated

When Intervention Becomes Imperative: A Case Report of Spontaneous Vulvar Edema During Pregnancy

Spontaneous idiopathic vulvar edema during the second trimester is a rare condition. The approach to managing this condition involves relieving symptoms, identifying underlying causes, and implementing appropriate treatment. Managing such cases during pregnancy is challenging because of concerns for potential adverse fetal outcomes. Conservative management expects the condition to be relieved spontaneously postpartum, whereas invasive treatment offers a more rapid resolution. Treatment choices are controversial because each method has its pros and cons and influences the delivery process to a certain extent. Surgical drainage becomes a viable option when patients are not responsive to medications. We report a case of spontaneous massive vulvar edema in a 22-year-old primigravida in her 23rd week of pregnancy. After ruling out other notable causes of vulvar edema, we decided to intervene using an invasive procedure because she complained of progressive symptoms and discomfort. Subsequently, the edema subsided postprocedure, and the patient experienced successful labor with no complications. This report aims to alert clinicians that drainage attempts should be considered in pregnant patients with worsening symptoms

People's options on forest land use

The series of draft and finalised Working Papers of the Sida I Sarec funded research co­ operation project "People's options on forest land use" has several objectives. In conjunction with ongoing field work, the Working Paper serves as an instrument to make available to national research institutions and other interested parties a preliminary documentation, directly related to the field work. The Working Papers are used for workshops and seminars, the objective of which is to discuss and further develop the issues considered relevant in the national and local context. They are also used as reference documents in relation to other work with the national authorities at central and local levels. The Working Papers, especially in draft form, might lack in academic standards and style and there are only scattered references to other research, but they could still serve the purpose of developing co-operation and further discussions. The authors warmly receive comments on the content. Any citation of this paper in research publications is not agreed upon at this stage without approval by the authors. In this paper, Bo Ohlsson is the author of chapter 3.3, 4.3, 5.2-5.4, 6.1-6.4 and Annex B-C. Mrs R. Kajsa Sandewall and Mrs Tran Thi Binh have written part 3.4, 4.1 and 5.5. Mats Sandewall has authored the remaining parts and he has also edited the report. Mr Pham Quoc Hung has run the final scenarios with the Area Production Model, APM. The work has been co-ordinated and greatly facilitated by Mr Vo Tri Chung. The principal researchers have discussed and are jointly responsible for the conclusions. ACKNOWLEDGEMENTS This paper has been prepared with the direct or indirect support and co-operation of a number of persons and organisations to whom we are sincerely grateful. We would particularly like to mention the following offices and their staff. The Forest Inventory and Planning Institute, Hanoi The Vietnamese and Swedish part of the Mountain Rural Development Programme The Ministry of Agriculture and Rural Development The People's Committee, Lao Cai Province The Agricultural and Rural Development Office, Lao Cai Province Muong Khuong District Ban Lau Commune The People of Lang Ha Village Sida/Sarec, which provide the funds for our work. We realise that without the generous support provided, it had not been possible to conduct our studies in a remote and sensitive area on such short notice and with the excellent arrangements that we have experienced. We have felt a sincere and positive interest from all concerned and it has greatly facilitated and stimulated our work

Health risk due to exposure to chlorpyrifos for farmers in Thai Binh: Probabilistic risk assessment

Farmers in Vietnam are at high risk of exposure to pesticides, especially with chlorpyrifos, the most common insecticide registered for use in 2009 in Vietnam. The purpose of this study was to assess the health risks of chlorpyrifos exposure in farmers who were pesticide applicators. The research method included three steps: (i) 24-hour urine samples taken from farmers to analyse trichlorpyridinol (TCP), the main metabolite of chlorpyrifos, and then TCP was converted to Absorbed Daily Dose (ADD); (ii) dose-response (RADD) corresponding to acute effects on the nervous system was obtained and recalculated from epidemiologic studies on human population; (iii) the health risk of chlorpyrifos with farmers was evaluated using probabilistic health risk assessment approach with 10,000 trials simulated by Monte Carlo technique. The results showed that the baseline exposure level (ADDB) ranged from 0.03 - 1.98 µg/kg/d, and post-application exposure level (ADDA) ranged from 0.35 - 94 µg/kg/d. The total exposure level (ADDT), ranged from 0.4 - 94.2 µg/kg/d. Dose-response corresponding to neurological adverse effects (RADD) ranged from 5-181 µg/kg/d. The Hazard Quotient calculated from ADD and RADD revealed that the baseline exposure level did not contribute to a significant adverse effect, however the post-application and total exposure levels caused a high risk of adverse effects to farmers who were pesticide applicators at 33%. A needs assessment and intervention studies need to be conducted to explore methods to reduce the risks due to chlorpyrifos exposure among farmers

Design and Experimental Validation of a 3-DOF Force Feedback System Featuring Spherical Manipulator and Magnetorheological Actuators

This research focuses on the development of a new 3-DOF (Degree of Freedom) force feedback system featuring a spherical arm mechanism and three magnetorheological (MR) brakes, namely two rotary MR brakes and one linear MR brake. The first rotary MR brake is integrated in the waist joint to reflect the horizontal tangent force, the other rotary MR brake is integrated in the shoulder joint to reflect the elevation tangent force, while the linear MR brake is integrated in the sliding joint of the arm to reflect the radial force (approach force). The proposed configuration can reflect a desired force to the operator at the end-effectors of the arm independently in 3 DOFs by controlling the current applied to the coils of the MR brakes. After the introduction, the configuration of the proposed force feedback system is presented. Afterward, the design and conducted simulation of the MR brakes for the systems are provided. The prototype of the force feedback system, which was manufactured for the experiment, is then presented as well as some of the obtained experimental results. Finally, the proposed control system is presented and its implementation to provide a desired feedback force to the operator is provided

TAX COMPLIANCE OF SMALL AND MEDIUM ENTERPRISES: A CASE STUDY IN THUA THIEN HUE

Tax compliance is the concern of many researchers and tax managers. Based on secondary data from tax authorities and primary data collected from 362 small and medium enterprises (SMEs), we assess the tax compliance of small and medium enterprises. Descriptive statistics and one-way analysis of variance are used to analyse the data. The results show that SMEs receive various types of support to enhance their tax compliance. Further, both secondary and primary data indicate that SMEs have an adequate level of tax compliance. However, there are differences among sectors concerning tax declaration assessment. Based on these results, we discuss and propose several managerial and policy measures to improve SMEs’ tax compliance.Tuân thủ thuế là đề tài nhận được sự quan tâm của nhiều nhà nghiên cứu cũng như các nhà quản lý thuế. Mục tiêu của bài viết này nhằm đánh giá tuân thủ thuế đối với doanh nghiệp thuộc Cục Thuế tỉnh Thừa Thiên Huế quản lý. Trên cơ sở tiếp cận dữ liệu thứ cấp từ cơ quan thuế và thông qua khảo sát từ 362 doanh nghiệp nhỏ và vừa trên địa bàn tỉnh Thừa Thiên Huế, nghiên cứu đã đánh giá tuân thủ thuế của doanh nghiệp nhỏ và vừa thông qua các kỹ thuật thống kê mô tả, phân tích phương sai một yếu tố (ANOVA). Kết quả nghiên cứu cho thấy mức độ tuân thủ thuế của doanh nghiệp nhỏ và vừa là chưa tốt, có sự khác biệt giữa các doanh nghiệp thuộc các lĩnh vực hoạt động khác nhau trong đánh giá về kê khai thuế. Trên cơ sở đó, những hàm ý chính sách quản lý trong việc gia tăng tuân thủ thuế của doanh nghiệp nhỏ và vừa cũng được đề xuất trong bài viết

Application of Machine Learning in Epileptic Seizure Detection

Epileptic seizure is a neurological condition caused by short and unexpectedly occurring electrical disruptions in the brain. It is estimated that roughly 60 million individuals worldwide have had an epileptic seizure. Experiencing an epileptic seizure can have serious consequences for the patient. Automatic seizure detection on electroencephalogram (EEG) recordings is essential due to the irregular and unpredictable nature of seizures. By thoroughly analyzing EEG records, neurophysiologists can discover important information and patterns, and proper and timely treatments can be provided for the patients. This research presents a novel machine learning-based approach for detecting epileptic seizures in EEG signals. A public EEG dataset from the University of Bonn was used to validate the approach. Meaningful statistical features were extracted from the original data using discrete wavelet transform analysis, then the relevant features were selected using feature selection based on the binary particle swarm optimizer. This facilitated the reduction of 75% data dimensionality and 47% computational time, which eventually sped up the classification process. After having been selected, relevant features were used to train different machine learning models, then hyperparameter optimization was utilized to further enhance the models’ performance. The results achieved up to 98.4% accuracy and showed that the proposed method was very effective and practical in detecting seizure presence in EEG signals. In clinical applications, this method could help relieve the suffering of epilepsy patients and alleviate the workload of neurologists

A Compartmentalized Neuronal Cell-Culture Platform Compatible With Cryo-Fixation by High-Pressure Freezing for Ultrastructural Imaging

The human brain contains a wide array of billions of neurons and interconnections, which are often simplified for analysis in vitro using compartmentalized microfluidic devices for neuronal cell culturing, to better understand neuronal development and disease. However, such devices are traditionally incompatible for high-pressure freezing and high-resolution nanoscale imaging and analysis of their sub-cellular processes by methods including electron microscopy. Here we develop a novel compartmentalized neuronal co-culture platform allowing reconstruction of neuronal networks with high variable spatial control, which is uniquely compatible for high-pressure freezing. This cryo-fixation method is well-established to enable high-fidelity preservation of the reconstructed neuronal networks and their sub-cellular processes in a near-native vitreous state without requiring chemical fixatives. To direct the outgrowth of neurites originating from two distinct groups of neurons growing in the two different compartments, polymer microstructures akin to microchannels are fabricated atop of sapphire disks. Two populations of neurons expressing either enhanced green fluorescent protein (EGFP) or mCherry were grown in either compartment, facilitating the analysis of the specific interactions between the two separate groups of cells. Neuronally differentiated PC12 cells, murine hippocampal and striatal neurons were successfully used in this context. The design of this device permits direct observation of entire neuritic processes within microchannels by optical microscopy with high spatial and temporal resolution, prior to processing for high-pressure freezing and electron microscopy. Following freeze substitution, we demonstrate that it is possible to process the neuronal networks for ultrastructural imaging by electron microscopy. Several key features of the embedded neuronal networks, including mitochondria, synaptic vesicles, axonal terminals, microtubules, with well-preserved ultrastructures were observed at high resolution using focused ion beam – scanning electron microscopy (FIB-SEM) and serial sectioning – transmission electron microscopy (TEM). These results demonstrate the compatibility of the platform with optical microscopy, high-pressure freezing and electron microscopy. The platform can be extended to neuronal models of brain disease or development in future studies, enabling the investigation of subcellular processes at the nanoscale within two distinct groups of neurons in a functional neuronal pathway, as well as pharmacological testing and drug screening.ISSN:1662-453XISSN:1662-454

Parameter-Adaptive Event-Triggered Sliding Mode Control for a Mobile Robot

Mobile robots have played a vital role in the transportation industries, service robotics, and autonomous vehicles over the past decades. The development of robust tracking controllers has made mobile robots a powerful tool that can replace humans in industrial work. However, most of the traditional controller updates are time-based and triggered at every predetermined time interval, which requires high communication bandwidth. Therefore, an event-triggered control scheme is essential to release the redundant data transmission. This paper presents a novel parameter-adaptive event-trigger sliding mode to control a two-wheeled mobile robot. The adaptive control scheme ensures that the mobile robot system can be controlled accurately without the knowledge of physical parameters. Meanwhile, the event trigger sliding approach guarantees the system robustness and reduces resource usage. A simulation in MATLAB and an experiment are carried out to validate the efficiency of the proposed controller