Mobile Wireless Technologies Research Articles

Assessment of the Barriers and Enablers of the Use of mHealth Systems in Sub-Saharan Africa According to the Perceptions of Patients, Physicians, and Health Care Executives in Ethiopia: Qualitative Study.

Digital technologies are increasingly being used to deliver health care services and promote public health. Mobile wireless technologies or mobile health (mHealth) technologies are particularly relevant owing to their ease of use, broad reach, and wide acceptance. Unlike developed countries, Sub-Saharan Africa experiences more challenges and obstacles when it comes to deploying, using, and expanding mHealth systems. In addition to barriers, there are enabling factors that could be exploited for the design, implementation, and scaling up of mHealth systems. Sub-Saharan Africa may require tailored solutions that address the specific challenges facing the region. The overall aim of this study was to identify the barriers and enablers for using mHealth systems in Sub-Saharan Africa from the perspectives of patients, physicians, and health care executives. Multi-level and multi-actor in-depth semistructured interviews were employed to qualitatively explore the barriers and enablers of the use of mHealth systems. Data were collected from patients, physicians, and health care executives. The interviews were audio recorded, transcribed verbatim, translated, and coded. Thematic analysis methodology was adopted, and NVivo software was used for the data analysis. Through this rigorous study, a total of 137 determinants were identified. Of these determinants, 68 were identified as barriers and 69 were identified as enablers. Perceived barriers in patients included lack of awareness about mHealth systems and language barriers. Perceived enablers in patients included need for automated tools for health monitoring and an increasing literacy level of the society. According to physicians, barriers included lack of available digital health systems in the local context and concern about patients' mHealth capabilities, while enablers included the perceived usefulness in reducing workload and improving health care service quality, as well as the availability of mobile devices and the internet. As perceived by health care executives, barriers included competing priorities alongside digitalization in the health sector and lack of interoperability and complete digitalization of implemented digital health systems, while enablers included the perceived usefulness of digitalization for the survival of the highly overloaded health care system and the abundance of educated manpower specializing in technology. mHealth systems in Sub-Saharan Africa are hindered and facilitated by various factors. Common barriers and enablers were identified by patients, physicians, and health care executives. To promote uptake, all relevant stakeholders must actively mitigate the barriers. This study identified a promising outlook for mHealth in Sub-Saharan Africa, despite the present barriers. Opportunities exist for successful integration into health care systems, and a user-centered design is crucial for maximum uptake.

On the Quasistationarity of the Ambient Electromagnetic Field Generated by Wi-Fi Sources

In recent decades, the widespread use of mobile phones and wireless technologies has led to a significant increase in radiofrequency electromagnetic fields (RF-EMFs), raising concerns about continuous RF-EMF exposure among the general population. Recent research indicates that real-life RF signals are more biologically active than controlled laboratory signals with a low variability, suggesting that living organisms can adapt to EMF exposure when the pattern has a low variability. However, using real-life sources with unpredictable variation signals in biological experiments contradicts the principle of experiment controllability. This paper aims to investigate the nature of signals generated by current sources of ambient EMFs in terms of stationarity, with the goal of replicating them in biological experiments to study the effects of EMF exposure. Employing a range of statistical methodologies, starting with descriptive statistical analysis and progressing to the advanced APDP and APTF methods, an examination is conducted on a collection of Wi-Fi signal recordings across various operating modes, with particular attention given to video streaming. The chosen datasets are scrutinized with respect to their adherence to a Gaussian distribution and the concept of stationarity. The results indicate that the observed Wi-Fi signals lack stationarity in both the time and frequency domains. However, based on the analytical findings, it is possible to generate signals in frequency that authentically replicate Wi-Fi signals, accounting for nonstationarity considerations.

TOFDS: A Two-Stage Task Execution Method for Fake News in Digital Twin-Empowered Socio-Cyber World

Owing to the breakthrough in mobile wireless communication technologies, almost everyone has been immersed into social networks, while fake news and misinformation are also being pushed into people’s minds with astonishing speed and breadth. The rising disparity between limited computing resources and the exploding news size necessitates innovative solutions to handle the challenge posed by booming data volume and make it more likely to differentiate fake news. In response to the aforementioned dilemma, the social-aware computation offloading system is analyzed, where the digital twin (DT) paradigm is used to simulate tasks offloading and assess the associated costs. Next, to obtain the best offloading choice, we fully consider the social relationship constraints and further propose an online task execution method that includes two stages of cluster selection and computing offloading, named TOFDS. Specifically, it exploits the technologies from multiobjective optimization and deep reinforcement learning (DRL) and realizes the joint optimization of resource utilization, load balancing, service latency, and energy consumption. Eventually, the comparative experiments demonstrate that TOFDS performs well when dealing with fake news data and can adapt to changes in dataset size and service clusters.

Does mHealth influence community health worker performance in vulnerable populations? A mixed methods study in a multinational refugee settlement in Uganda.

Community Health Workers (CHWs) provide healthcare in under-served communities, including refugee settlements, despite various challenges hindering their performance. Implementers have adopted mobile wireless technologies (m-Health) to improve the performance of CHWs in refugee settlements. We assessed the CHWs' performance and associated factors in a multi-national refugee settlement, operating mHealth and paper-based methods. This cross-sectional study employed quantitative and qualitative data collection methods. Data for 300 CHWs was collected from implementing partners' (IPs) databases. Nine focus group discussions (FGDs) with the CHWs and community members, two in-depth interviews (IDIs) with CHW leaders, and eight key informant interviews (KIIs) with six IPs and two local leaders were conducted. The qualitative data were analysed thematically using AtlasTi version 9 while the quantitative data were analysed at the univariate, bivariate and multivariable levels using Stata version14. The study found that only 17% of the CHWs performed optimally. The factors that significantly influenced CHW performance included education level: secondary and above (APR: 1.83, 95% CI: 1.02-3.30), having a side occupation (APR: 2.02, 95% CI: 1.16-3.52) and mHealth use (APR: 0.06, 95% CI: 0.02-.0.30). The qualitative data suggested that performance was influenced by the number of households assigned to CHWs, monetary incentives, adequacy of materials and facilitation. Particularly, mHealth was preferred to paper-based methods. Overall, the CHWs' performance was sub-optimal; only 2 in 10 performed satisfactorily. The main factors that influenced performance included the level of education, use of mHealth, having another occupation, workload and incentivisation. CHWs and IPs preferred mHealth to paper-based methods. IPs should work to improve refugee settlement working conditions for the CHWs and adopt mHealth to improve CHW performance.

Organizing and Sharing Medical Knowledge Among Anesthesiology and Intensive care Residents: Evaluating Existing Practices and the Feasibility of Implementing a Dedicated Multiplatform Application.

Treating patients with up-to-date medical knowledge is an ongoing goal for healthcare workers and implies efficient knowledge management at the point of care. Widely available mobile wireless technologies influence practices but a significant gap remains between technological possibilities and actual usage. The purpose of this study was to analyze residents' baseline practices in managing medical knowledge and to evaluate the use and impact of an innovative multiplatform application dedicated to anesthesiology and intensive care residents. This study took place in Rennes Teaching Hospital and comprised two distinct surveys. First, in April 2018, all residents received a ten-items online survey focusing on managing medical knowledge. Then, through a second online survey constituted of ten items, we sought to assess the use of a new multiplatform cloud-based application named "DansMaBlouse", dedicated to sharing and indexing medical knowledge, in anesthesiology and intensive care residents. Among 148 residents that answered the evaluation survey, the most sought out pieces of information in clinical setting were a phone or fax number (74%), drugs' characteristics (68%) and expert guidelines (57%). The main sources were senior staff (68%), medical databases (60%) and an Internet search engine (59%). Computers and smartphones were more frequently used than bound paper notebooks. After implementation of the multiplatform application DansMaBlouse, fifty-nine (82%) of the 72 residents that answered the evaluation survey reported using the application and 39% used it more than ten times. Among application users, 90% found it easy to use and 92% agreed that it improved point-of-care access to knowledge. Accessing appropriate medical knowledge at the point of care remains an issue for residents and can be improved by a multiplatform application combining personal and shared up-to-date resources.

A Three-Factor-Based Authentication Scheme of 5G Wireless Sensor Networks for IoT System

Internet of Things (IoT) is an expanding technology that facilitate physical devices to inter-connect each other over a public channel. Moreover, the security of the next-generation wireless mobile communication technology, namely 5G with IoT, has been a field of much interest among researchers in the last several years. Previously, Sharif et al. had suggested an IoTbased lightweight three-party authentication scheme proclaiming a secured scheme against different threats. However, it was found that the scheme could not achieve user anonymity and guarantee session key security. Additionally, the scheme fails to provide proper authentication in the login phase, and it s unable to update a new password in the password change phase. Thus, we propose an improved three-factor-based data transmission authentication scheme (TDTAS) to address the weaknesses. The formal security analysis has been proved using the Real-or-Random (RoR) model. The informal security analysis demonstrates that the scheme is secure against several known attacks and achieves more security features. In addition, the comparison of the work with other related schemes demonstrates the proposed scheme has less communicational and storage costs.

An Efficient and Secure Routing Approach in Vehicular Adhoc Networks (VANETs)

It is becoming increasingly difficult to locate someone who has not been exposed to wireless mobile technologies due to how quickly they are being adopted. To create a mobile adhoc network, these devices could be linked directly or indirectly using wireless channels. Routing in a network is the process of determining the best path for flow from a source to a destination. The fundamental issues with routing in VANETs are dynamic topology and unreliable connection statuses. Instead than broadcasting across the whole network, the routing mechanism focuses on individual routes. The ability to provide flexibility and scalability in routing is thus feasible. Experiments in VANET contexts, namely hand-held device-based VANETs, have shown benefits of the suggested routing technique. This allows us to evaluate our protocol in terms of packet delivery ratio, control overhead and end-to-end delay.

THE IMPACT OF EFL TEACHERS’ CAPACITIES TO USE MOBILE TECHNOLOGY FOR ENGLISH TEACHING AT A COLLEGE IN HO CHI MINH CITY, VIETNAM

Mobile gadgets, mobile teaching, and mobile learning aids have quickly risen to prominence in the fourth industrial revolution. Mobile devices' intelligent features enable teaching and learning anywhere and at any time using wireless networks.. Mobile-assisted language learning (MALL) is therefore anticipated to improve learners' English proficiency. However, before mobile teaching and learning applications are developed, the teachers' capacity to use wireless mobile technology should be verified. The present paper examines how EFL instructors in Ho Chi Minh City, Vietnam, use mobile devices to instruct English. Quantitatively, 45 EFL teachers participated in the study and responded within 15 minutes to a questionnaire containing 12 statements. Three open-ended interview questions were given to ten of them, and the data was obtained through a qualitative one. According to research findings, EFL teachers are self-assured in their ability to employ mobile technology and adjust the unpredictable changes of modern high-tech portables to aid in their English teaching

Energy Efficiency of Mobile Devices Using Fuzzy Logic Control by Exponential Weight with Priority-Based Rate Control in Multi-Radio Opportunistic Networks

The rapid development of mobile devices and wireless network technologies have made them indispensable. This has created a demand for faster networks and longer battery life. The assurance of a stable network service and the enhancement of network experiences for mobile devices is equally crucial to meeting these demands. To address these challenges, mobile devices employ various techniques to decrease power consumption when they connect to wireless networks. Moreover, enhancing the endurance of mobile devices to maintain stable network services is critical when using wireless networks. In this paper, we propose a dual-radio opportunistic network for energy efficiency (DRONEE)–exponential weight with priority-based on rate control (WPRC) method which can extend and enhance the DRONEE hybrid network. By leveraging fuzzy logic control (FLC) and quality of service (QoS), our proposed method effectively solves the weighting problem in the DRONEE–weight (DRONEE–W) method. Through efficient allocation of network resources within each cluster, we minimize resource wastage and maximize resource utilization. Simulation results demonstrate the superior performance of our DRONEE–WPRC method in terms of throughput, buffer size, delay time, and power consumption compared to other methods. Therefore, our proposed method achieves optimal network resource allocation and energy efficiency.

Electromagnetic Fields - Do They Pose a Cardiovascular Risk?

Mobile wireless communication technologies have now become an everyday part of our lives, 24 hours a day, 7 days a week. Monitoring the autonomous system under exposition to electromagnetic fields may play an important role in broading of our still limited knowledge on their effect on human body. Thus, we studied the interaction of the high frequency electromagnetic field (HF EMF) with living body and its effect on the autonomic control of heart rate using Heart Rate Variability (HRV) linear and nonlinear analyses in healthy volunteers. A group of young healthy probands (n=30, age mean: 24.2 ± 3.5 years) without any symptoms of disease was exposed to EMF with f=2400 MHz (Wi Fi), and f=2600 MHz (4G) for 5 minutes applied on the chest area. The short-term heart rate variability (HRV) metrics were used as an indicator of complex cardiac autonomic control. The evaluated HRV parameters: RR interval (ms), high frequency spectral power (HF-HRV in [ln(ms2)]) as an index of cardiovagal control, and a symbolic dynamic index of 0V %, indicating cardiac sympathetic activity. The cardiac-linked parasympathetic index HF-HRV was significantly reduced (p =0.036) and sympathetically mediated HRV index 0V % was significantly higher (p=0.002) during EMF exposure at 2400 MHz (Wi-Fi), compared to simulated 4G frequency 2600 MHz. No significant differences were found in the RR intervals. Our results revealed a shift in cardiac autonomic regulation towards sympathetic overactivity and parasympathetic underactivity indexed by HRV parameters during EMF exposure in young healthy persons. It seems that HF EMF exposure results in abnormal complex cardiac autonomic regulatory integrity which may be associated with higher risk of later cardiovascular complications already in healthy probands.

Design of a Smart Cabin Lighting System Based on Internet of Things

With the rapid advancements in mobile devices and wireless network technologies, the Internet of Things (IoT) has become more powerful and popular than ever. The aim of IoT is to efficiently control various types of objects through wireless communications. This paper aims to design an IoT-based smart lighting system that reduces development costs and saves power consumption. Unlike public open spaces, the focus of this paper is on ship cabin spaces. As ship cabins have unique properties, such as requiring gas-based power generation and preferring a wireless environment, designing a smart cabin lighting system is crucial and has significant commercial value. The smart cabin lighting system is designed with four features. Firstly, it can automatically control the lighting devices around people using position-sensitive devices. Secondly, it enables setting on/off and adjusting the luminance for lighting devices through Touch Keypads. Thirdly, the system can be controlled using an app to turn on/off and adjust the luminance of lighting devices. Lastly, the lighting devices equipped with sensors collect specific data on cloud servers for analysis. The underlying communication protocol used to interconnect the smart lighting devices, sensors, and Touch Keypads is Zigbee. The smart cabin lighting system can be applied to marine lighting, thus improving the commercial value of enterprises related to marine lighting.

Dynamique concurrentielle : la retenue mutuelle entre concurrents monopoints sur un marché récemment libéralisé

This paper investigates mutual forbearance as a rivalrous mode in a sector with single-market competitors. For this purpose, we use multidimensional strategic sequences as a theoretical lens to analyze the evolution of competitive interactions in the Algerian mobile telecommunications sector following the introduction of third-generation wireless mobile telecommunications technology (3G), an event expected to stimulate competition. The findings show a de-escalation of competitive aggressiveness after the 3G introduction and reveal the existence of mutual forbearance among single-market competitors. This paper discusses the factors and mechanisms of mutual forbearance in sectors with single-market competitors.

Base Station Energy Use in Dense Urban and Suburban Areas

Growing energy consumption is a global problem. The information and communications technology (ICT) industry is in a critical role as an enabler of energy savings in other sectors. However, the power consumption of the ICT sector also needs to be addressed, to contribute to the overall reduction of power consumption and carbon emissions. A new era has begun as the fifth generation (5G) mobile data connection rollouts are advancing globally and are expected to reach a 10% share of end-user devices and connections by 2023. The available references on energy consumption in global mobile networks are rather old and highly averaged – only estimates of energy consumption relative to data volumes are available. There is an information gap regarding the energy consumption of emerging 5G and advanced 4G technologies. Therefore, it has been difficult to understand the actual electricity consumption differences between generations and spatially aggregated electricity consumption once these generations are combined to offer capacity and coverage. This article fills this gap by providing a reference on the energy consumption of base transceiver stations for reported mobile data usage for different Radio Access Technologies; 3G, 4G and 5G respectively. To the best of our knowledge, there is no reference to scientific research on the comparison of energy intensity per square kilometer for 3G, 4G and 5G mobile radio technologies, using actual operator data. The objective of this research was to improve the understanding of the actual energy consumption of different Radio Access Technologies (RAT). The results also give insight to decision makers on when to modernize the operator radio access network. The article reports on the results of field measurements on data and visitor volumes and shares of different RATs. The research contains two statistical RAT combination cases, one representing the European average and the other Finnish mobile networks. The analyses were done for dense urban (DU) and suburban (SU) areas.

System-Level Performance Evaluation of 5G Use Cases for Industrial Scenarios

The Fifth Generation (5G) of mobile radio technologies represents a change of paradigm in mobile communications by serving not only users but also verticals. Given the increasing number of use cases identified for industrial scenarios, Third Generation Partnership Project (3GPP) defined a set of relevant use cases for Indoor Factory (InF) scenarios with their associated requirements and channel models to theoretically study signal propagation in these environments. In this context, this work first studies these InF scenarios by means of System-level Simulations (SLSs). By selecting the most demanding sub-scenario, we then carry out a performance evaluation of the specific 5G industrial use cases with the most stringent requirements, following 3GPP assumptions. Three use cases from the thirteen defined by the 5G Alliance for Connected Industries and Automation (5G-ACIA) have been carefully selected: massive wireless sensor networks, autonomous mobile robots, and augmented reality. The results demonstrate the fulfillment of the performance requirements in each use case, validating 5G as an enabler technology for future industry verticals.

Performance Evaluation of CAM Broadcast Message and Vehicle Safe Distance Under Nakagami-m Radio Channel Conditions

Many potentials exist in the 5G era for effectively managing vehicle safety on the road. The European Telecommunications Standards Institute (ETSI) 5G C-V2X standards for Cooperative Aware Messages for Intelligent Transport Systems (ITS) provide necessary upper-layer requirements for safety message distribution between vehicles using Cooperative Aware Messages (CAM). In addition, the Long Term Evolution (LTE) mobile radio technology in Release-14 has two modes of communication, mode 3 and mode 4, to facilitate vehicle-to-vehicle communications. The focus of this study is on vehicle communications in a mode 3 environment, in which the cellular network chooses and manages the radio services utilised by vehicles for direct vehicle-to-vehicle communication. The performance modelling of Safety Avoidance Time (AT) and safety CAM message broadcast for vehicle-to-vehicle communication in LTE C-V2X under the Nakagami-m radio channel, which has two components, LOS and NLOS, is studied in this thesis. Under the Nakagami-m radio channel, the LOS and NLOS components will affect the CAM message disseminating to other vehicles within safe time gaps. Therefore, the aim of this study is to look into the various radio channel characteristics in a vehicle-to-vehicle communication environment that are related to CAM message dissemination and vehicle safe distance, as well as to evaluate the performance of the relationship between PDR, throughput, and transmit power proportional to safe time gaps under the Nakagami-m radio channel with various setting shape factors.

Research on Architecture Design of Mobile Video Surveillance System in Information Room Based on Intelligent Robot Technology

With the gradual development of information technology, the idea of combining mobile robot and wireless remote control technology is adopted to build a wireless network platform between a computer and robot. At present, there are conditions to realize this idea. In this idea, the wireless data transmission can be realized on the platform. Users can remotely control and access the monitoring system of the computer room and set up alarm systems and detectors, so as to monitor the working conditions of the robot at the computer terminal, truly realize the man-machine coordination, and ensure that the robot can complete the specified tasks well in various complex environments. This research first deeply analyzes the current development status and existing problems of the information room monitoring technology and then puts forward the mobile video monitoring system architecture of the information room based on the intelligent robot monitoring technology. The system architecture integrates computer technology, network technology, and control technology. With the continuous updating of technology, video surveillance has also entered the mobile era. Combined with the timely monitoring video acquisition system of mobile robots, it solves the current working environment for many industries and enterprises. Using robot chassis technology, it designs the corresponding bottom hardware control and upper equipment to achieve data acquisition with related equipment. The mobile video surveillance system solves the problems encountered by the traditional video surveillance system and can monitor video images through remote operation and centrally monitors the operation status of the equipment in the room and the environmental status of the room, which is more conducive to improving the management efficiency. It provides a new idea to ensure the safe and stable operation of various equipment and systems in various places.

Optical Front/Mid-Haul With Open Access-Edge Server Deployment Framework for Sliced O-RAN

The fifth-generation of mobile radio technologies is expected to be agile, flexible, and scalable while provisioning ultra-reliable and low-latency communication (uRLLC), enhanced mobile broadband (eMBB), and massive machine type communication (mMTC) applications. An efficient way of implementing these is by adopting cloudification, network function virtualization, and network slicing techniques with open-radio access network (O-RAN) architecture where the base-band processing functions are disaggregated into virtualized radio unit (RU), distributed unit (DU), and centralized unit (CU) over front/mid-haul interfaces. However, cost-efficient solutions are required for designing front/mid-haul interfaces and time-wavelength division multiplexed (TWDM) passive optical network (PON) appears as a potential candidate. Therefore, in this paper, we propose a framework for the optimal placement of RUs based on long-term network statistics and connecting them to open access-edge servers for hosting the corresponding DUs and CUs over front/mid-haul interfaces while satisfying the diverse QoS requirements of uRLLC, eMBB, and mMTC slices. In turn, we formulate a two-stage integer programming problem and time-efficient heuristics for users to RU association and flexible deployment of the corresponding DUs and CUs. We evaluate the O-RAN deployment cost and latency requirements with our TWDM-PON-based framework against urban, rural, and industrial areas and show its efficiency over the optical transport network (OTN)-based framework.

Development of a concept for cybersecurity metrics classification

The development of the IT industry and computing resources allows the formation of cyberphysical social systems (CPSS), which are the integration of wireless mobile and Internet technologies and the combination of the Internet of things with the technologies of cyberphysical systems. To build protection systems, while minimizing both computing and economic costs, various sets of security profiles are used, ensuring the continuity of critical business processes. To assess/compare the level of CPSS security, various assessment methods based on a set of metrics are generally used. Security metrics are tools for providing up-to-date information about the state of the security level, cost characteristics/parameters from both the defense and attack sides. However, the choice of such sets is not always the same/understandable to the average person. This, firstly, leads to the absence of a generally accepted and unambiguous definition, which means that one system is more secure than another. Secondly, it does not take into account the signs of synergy and hybridity of modern targeted attacks. Without this knowledge, it is impossible to show that the metric measures the security level objectively. Thirdly, there is no universal formal model for all metrics that could be used for rigorous analysis. The paper explores the possibility of defining a basic formal model (classifier) for analyzing security metrics. The proposed security assessment model takes into account not only the level of secrecy of information resources, the level of provision of security services, but also allows, based on the requirements put forward, forming the necessary set of security assessment metrics, taking into account the requirements for the continuity of business processes. The average value of the provision of security services to CPSS information resources is 0.99, with an average value of the security level of information resources of 0.8

Application of wireless mobile communication technology in nursing and pharma profession

At present, the commonly used remote physiological information monitoring method in the field of nursing is limited in application, and has poor real-time performance and anti-interference ability. Therefore, through the research of remote monitoring method based on wireless mobile communication, the application of wireless mobile communication technology in nursing professional field was explored. Using ZigBee technology to build a wireless mobile communication network architecture, through which the ECG data analysis and diagnosis of patient monitoring terminal are transmitted. Using TDOA ranging technology to quickly locate the position of patients, so as to ensure the medical effect. Compared with the traditional remote monitoring method, the wireless mobile communication technology has the advantages of fast response, stable monitoring and high sensitivity.

Chinese Online Language Dissemination from the Perspective of Mobile Information System

The emergence of new media technology will inevitably bring new changes to people's daily communication. The development and change of society supports the development and change of language. Language networks are created and developed along with Internet applications. It is a new variant of the traditional language adapted to the new media environment of the Internet Age. With the increasing popularity and importance of network media, network language has received extensive attention and research on local languages. This paper analyzes and investigates the dissemination of Chinese Internet language from the perspective of mobile information system. On the basis of researching and proposing the mobile information system model, the structure of the system is deeply analyzed, and the key characteristics and technologies of various fields are discussed. Wireless mobile terminal wireless Internet access technology, portable intelligent terminal mobile application development technology, and local database technology are very suitable for Chinese network analysis and research to reduce wireless connections, and the effective range is from 50 feet to 1000 feet. The article uses the communication theories and methods of linguistics, cultural studies, network neologism generation, and communication characteristics analysis. It uses students as examples to explore their online neologism use and dyslexia and their problem-solving strategies for obstacles. The results show that 50% of the students can accept the new words on the Internet very well, and 30% of the students do not understand it.