Number Of Potential Users Research Articles

Terms of use and network size: Evidence from online job boards and CV banks in the U.S.

Data on websites that hosted job boards and CV banks in the U.S. from 2000 to 2011 reveal that websites imposed fewer restrictions (in terms of the duration of use) and lower fees for job searchers relative to employers. This asymmetry in the treatment (or the terms of use) changed as the relative scarcity of job searchers and job vacancies in the labor market in which the websites offered their services changed. Compared with job searchers, employers faced less stringent restrictions and lower fees when job searchers were scarce relative to job openings. These adjustments imply that the value of using an employment website changes with the number of potential users and the probability of finding a quality match. We find that these adjustments were most pronounced for websites that relied exclusively on employers and job searchers for their content (job ads and CVs). Whereas existing literature on the role that network size plays in intermediaries’ decision-making has focused on prices, our findings reveal that this focus can overlook other adjustments that affect the terms of use. Given that these adjustments in our context may result in longer periods during which CVs and job ads remain online, our findings suggest that the optimal design of intermediaries must include tools that help users sort through stale information.

SIMULASI DISTRIBUTED BINARY POWER ALLOCATION PADA SISTEM RADIO KOGNITIF

Cognitive radio is a technology for wireless communication networks that employ the upcoming Dynamic Spectrum Access ( DSA ) . DSA technology allows users who do not have a license called the secondary spectrum users to use the licensed spectrum that primary users while not in use. Application of DSA by secondary users to improve the spectrum utilization efficiency without disrupting or causing interference to the primary user. Later developed into a multi - user cognitive radio or cognitive radio networks use frequency spectrum together with a primary user ( PU ).
 Methods switch 'off' the user who gives the biggest interference to PU is the best method with the greatest increase in performance, both the capacity and the number of active SU while the combination of methods switch 'off' the user who raised the largest overall interference with the method switches 'off' user given biggest interference to the PU is an alternative method that shows the consistency of performance improvement in the number of potential users over 10 and able to dominate the entire method over another is begun saturation and decreased capacity.
 Abstracts are made in two languages, English and Bahasa Indonesia. Abstract more about background, purpose, up to, the results of research, and manai research. Abstract contains up to 250 words, single write spaces with italics (Italics) for English abstracts. Below the abstract are listed keywords consisting of six words, where the first word is again the forward. Abstract in Indonesian can be a translation of an English translation. Tiff editor for abstract syncing for reasons of abstract content

Emerging Perspectives of Blockchains in Food Supply Chain Traceability Based on Patent Analysis

In the field of blockchain (BC) technology application in the food supply chain (FSC), a patent portfolio is collected, described, and analyzed using Latent Dirichlet Allocation (LDA) modeling, with the aim of obtaining insight into technology trends in this emerging and promising field. A patent portfolio consisting of 82 documents was extracted from patent databases using PatSnap software. The analysis of latent topics using LDA indicates that inventions related to the application of BCs in FSCs are patented in four key areas: (A) BC-supported tracing and tracking in FSCs; (B) devices and methods supporting application of BCs in FSCs; (C) combining BCs and other ICT technologies in FSC; and (D) BC-supported trading in FSCs. Patenting of BC technology applications in FSCs started during the second decade of the 21st century. Consequently, patent forward citation has been relatively low, while the family size confirms that application of BCs in FSCs is not yet widely accepted. A significant increase in the number of patent applications was registered after 2019, indicating that the number of potential users in FSCs is expected to grow over time. The largest numbers of patents originate from China, India, and the US.

Developing mobile software for foreign language learning

Problem. The subject of the study is an interactive mobile application in Java. To perform this work, the following tasks were set: analysis of programming environments and languages of development; analysis of methods for developing the logic and interface of the mobile application; development of an interactive mobile application in Java. Goal. The aim of the work is to develop a mobile application for learning a foreign language for the Android operating system, whose interface and logic will be modern, user-friendly and accessible to users. Methodology. The general concept of a mobile application for learning a foreign language is as follows: learning a foreign language offline, versatile learning (words, grammar), the presence of a motivational unit, simple design. The object of research is the process of building an interactive mobile application in Java for the Android operating system. In the course of the work, a study of programming languages and environments for the development of mobile applications was conducted. Programming languages such as: Java, C ++, C # were considered. Programming environments such as Android Studio, NetBeans and Eclipse were also analyzed. As a result, the Java programming language and Android Studio programming environment were chosen for the development of the mobile application. Two types of markup were selected: LinearLayout; ConstraintLayout. Results. The mobile application for learning a foreign language for the Android operating system was developed in Android Studio in two programming languages: Java (logic) and XML (interface). The aim to provide the application with modern interface and logic, to make it user-friendly and accessible to users was completed. Originality. Contribution has been made to the field of using smartphones for learning foreign languages. The sphere of using smartphones has been expanded with the use of all modern trends to the creation of mobile applications for learning foreign languages. Practicalvalue. Considering that the number of potential users will only increase in the nearest future, the developed mobile application for learning a foreign language is an ideal platform for educating those who want to develop and learn foreign languages for themselves, as well as for work, communication and travel.

Non-Bayesian Activity Detection, Large-Scale Fading Coefficient Estimation, and Unsourced Random Access With a Massive MIMO Receiver

In this paper, we study the problem of user activity detection and large-scale fading coefficient estimation in a random access wireless uplink with a massive MIMO base station with a large number $M$ of antennas and a large number of wireless single-antenna devices (users). We consider a block fading channel model where the $M$-dimensional channel vector of each user remains constant over a coherence block containing $L$ signal dimensions in time-frequency. In the considered setting, the number of potential users $K_\text{tot}$ is much larger than $L$ but at each time slot only $K_a<<K_\text{tot}$ of them are active. Previous results, based on compressed sensing, require that $K_a\leq L$, which is a bottleneck in massive deployment scenarios such as Internet-of-Things and unsourced random access. In this work we show that such limitation can be overcome when the number of base station antennas $M$ is sufficiently large. We also provide two algorithms. One is based on Non-Negative Least-Squares, for which the above scaling result can be rigorously proved. The other consists of a low-complexity iterative componentwise minimization of the likelihood function of the underlying problem. Finally, we use the discussed approximated ML algorithm as the decoder for the inner code in a concatenated coding scheme for unsourced random access, a grant-free uncoordinated multiple access scheme where all users make use of the same codebook, and the massive MIMO base station must come up with the list of transmitted messages irrespectively of the identity of the transmitters. We show that reliable communication is possible at any $E_b/N_0$ provided that a sufficiently large number of base station antennas is used, and that a sum spectral efficiency in the order of $\mathcal{O}(L\log(L))$ is achievable.

ProQuest African American Heritage

African American Heritage a database for African American family history research, provided by ProQuest. Here, the user has access to a wide variety of military, birth, marriage, cohabitation, death, and census records. Also included are records from the Freedman’s Bank and various registers of slaves and free(d) persons of color. The former was a bank chartered by the federal government to encourage and guide the economic development of African American communities in the period following the end of slavery in the U.S. The latter refers to records, maintained by a number of states prior to 1865, of slaves and free(d) persons of color. Also available to the user are contacts to a community of genealogy researchers, who can provide assistance and mentoring. The readability of the documents available here can vary. Some are too faded to read easily, even with magnification, and others are handwritten, which can make them difficult to interpret. Navigating, enlarging, and reducing documents can be done without difficulty, though the range of movement and magnification is somewhat limited. Documents can be browsed and/or searched for by title, author, publisher, date, subject, language (although, at present, English is the only language available), surname and personal name, and location.The search and browse options here are understandable and can produce useful results, though the number produced by any one query is usually not extensive, so multiple queries may be needed for any research project. Pricing for this database is determined by library or school size and the number of potential users, and consortia discounts are available (contact ProQuest for a specific price quote). Its licensing agreement is the same as those used for all ProQuest databases, and in its length and composition is quite average. The quality and quantity of content in this resource is not exceptional, but it will certainly be of use to those researching African American family history, and more generally Africana Studies, especially in the states indicated in this review.

Общие подходы к проектированию подсистемы доступа высокопроизводительных вычислительных систем

Mathematical modeling allows to create a digital model of a product, the so-called digital twin. Such digital twins are quite complex mathematical models, the description of which, as well as the calculation of their parameters and characteristics, is a very serious computational problem that can be solved on high-performance computing systems. However, a building a high-performance supercomputing system designed for solving problems of computer simulation of various physical processes is a difficult time-consuming task. The paper discusses basic approaches to design a login nodes subsystem for such high-performance supercomputing system, allowing to systematize and simplify the process of its development. The analysis of the main factors affecting the structure and composition of the login nodes subsystem is carried out. These factors include the number of potential users of a high-performance computing system; availability of categories of users of the system and their percentage; characteristics of computing tasks solved on the system; hardware platform chosen for building systems. An example of a methodology for calculating of the login nodes subsystem size is given.

Filmmaking courses for scientists help promote richer alternatives to chronological narratives

ABSTRACT Scientists have the tendency to communicate their scientific accounts using linearly structured narratives (Introduction, Methods, Results and Discussion; IMRAD). Likewise, the linear narrative is dominant – due to force of habit – when scientists prepare films about their research. Yet, this does not necessarily have to be the case for the new generation of scientists-as-filmmakers, who is trained to appreciate and apply alternative narrative structures. We evaluated the narrative structures of scientists from Swiss universities and research centres. Before the filmmaking courses, 94.1% of participants would use the linear narrative structure in their films, while the remaining participants would use one of the other alternative narrative types. However, after participating in the filmmaking courses, the number of potential users of the linear narrative fell almost 11-fold, and this type of narrative became the least popular. By contrast, after the courses the before-climax-backwards narrative experienced a 79-fold increase in potential use. The parallel, frame and end-backwards narratives had seven-, six- and four-fold increases, respectively. The filmmaking courses also dramatically increased the number of types of narratives that participants would consider using. Filmmaking courses for scientists help scientists-as-filmmakers make a clean break from linear narrative structures in favour of other more varied structures.

Weight-Bearing Estimation for Cane Users by Using Onboard Sensors.

Mobility is a fundamental requirement for a healthy, active lifestyle. Gait analysis is widely acknowledged as a clinically useful tool for identifying problems with mobility, as identifying abnormalities within the gait profile is essential to correct them via training, drugs, or surgical intervention. However, continuous gait analysis is difficult to achieve due to technical limitations, namely the need for specific hardware and constraints on time and test environment to acquire reliable data. Wearables may provide a solution if users carry them most of the time they are walking. We propose to add sensors to walking canes to assess user’s mobility. Canes are frequently used by people who cannot completely support their own weight due to pain or balance issues. Furthermore, in absence of neurological disorders, the load on the cane is correlated with the user condition. Sensorized canes already exist, but often rely on expensive sensors and major device modifications are required. Thus, the number of potential users is severely limited. In this work, we propose an affordable module for load monitoring so that it can be widely used as a screening tool. The main advantages of our module are: (i) it can be deployed in any standard cane with minimal changes that do not affect ergonomics; (ii) it can be used every day, anywhere for long-term monitoring. We have validated our prototype with 10 different elderly volunteers that required a cane to walk, either for balance or partial weight bearing. Volunteers were asked to complete a 10 m test and, then, to move freely for an extra minute. The load peaks on the cane, corresponding to maximum support instants during the gait cycle, were measured while they moved. For validation, we calculated their gait speed using a chronometer during the 10 m test, as it is reportedly related to their condition. The correlation between speed (condition) and load results proves that our module provides meaningful information for screening. In conclusion, our module monitors support in a continuous, unsupervised, nonintrusive way during users’ daily routines, plus only mechanical adjustment (cane height) is needed to change from one user to another.

Development of geo­model for concentration determination of hazardous chemicals in the atmosphere

A critical analysis of the approaches to the development of a model for determining the concentration of hazardous chemicals (HC) in the atmosphere, which are the basis of computer­aided environmental monitoring systems (CEMS) has been carried out. It has been established that the lack of effective functioning of the existing CEMS is determined by the imperfection of the models used to determine the concentration of atmospheric chemical concentration in the atmosphere. In addition, the organic disadvantage of such systems is their departmental affiliation and, as a result, the limited number of potential users. To improve the efficiency of the discussed class of systems, a concept of integrated use has been proposed, within the CEMS framework, elements of information and analytical systems for environmental monitoring, satellite image processing tools, geoinformation technologies, and also mathematical software for calculating the concentration of various types of atmospheric HCs. Building a CEMS based on this concept will provide an opportunity to significantly improve the efficiency of their functioning in the aspects of reducing the time for making decisions, as well as reducing the risk of making wrong decisions. The mathematical support of the CEMS is based on the “Gaussian” statistical model of HC emission, and is intended, along with geographic information technologies, to synthesize a geo­model of ground­level atmosphere pollution by HCs. As an illustrative example, the situation of the release of chemical waste in the area of Bila Tserkva (Kyiv region, Ukraine) is considered. Theoretical results form the methodological basis for the implementation of the applied information technology for the creation, deployment and operation of a decision support system for eliminating the consequences of an emergency situation caused by the proliferation of chemical water in the atmosphere

Evolution of multiple-access networks cellular and non-cellular — in historical perspective. Part 1

Introduction:The goal of this review is the analysis of evolution of the current and novel wireless networks, from secondgeneration (2D)tofifth generation(5G),as well as changes in technologies and their corresponding theoretical background andprotocols -from Bluetooth, WLAN, WiFi and WiMAXtoLTE, OFDM/OFDMA, MIMO and LTE/MIMO advanced technologies with new hierarchy of cellular maps design — femto/pico/micro/macro.Methods:We use new theoretical frameworkstodescribe advanced technologies, such as multicarrier diversity technique, OFDM and OFDM novel approach, new aspects ofMIMO description based on multi-beam antennas, design of various cellular maps based on new algorithms of femto/pico/micro/macrocell deployment, and the methodology of a new MIMO/LTE system integration based on multi-beam antennas.Results:We have created a new methodology for multi-carrier diversity description of novel multiple-access networks, forthe usage of OFDM/OFDMA modulation in ordertoovercome inter-user and inter-symbol interference in multiple-access networks, as well as multiplicative noises in multiple-access wireless networks caused by multi-ray phenomena. Finally, wehave suggested howtoovercome the propagation effects occurring in the terrestrial communication channels by using acombination of MIMO and LTE technologies based on multi-beam antennas. For these purposes, we present a new stochasticapproach which takes into account the terrain features, such as buildings' overlay profile, buildings' density around the base station and each user's antennas, andsoforth. These parameters allow ustoestimate the effects of fading as a multiplicativenoise source.Practical relevance:The new methodology of estimating the effects created by multiplicative noise and inter-user and inter-symbol interference in terrestrial wireless networks allows ustopredict a-priory practical aspects of the currentand new multiple-access wireless communication systems, like the potential number of users or the spectral efficiency ofuser channels for various configurations of cell deployment: femto, pico, micro, and macro, as well as the novel MIMO/LTE system configurations for future networks of the 4th and 5th generations.

Predictive analytics and disused railways requalification: Insights from a Post Factum Analysis perspective

Strategic decision making problems in the public policy domain typically involve the comparison of competing options by different stakeholders. This paper considers a real case study dealing with potential actions to be ranked for the regeneration of disused railways in Italy. The study involves multiple conflicting criteria such as an expected duration of construction works, costs, number of potential users, and new green areas. Within this context, we demonstrate that Post Factum Analysis (PFA) coupled with Decision Aiding supports the development of robust recommendations. The role of PFA is to highlight how the actions' performances need to be modified so that the recommendation is changed in a desired way. In particular, it highlights the minimal improvements that would warrant the feasibility of a currently impossible outcome (e.g., achieving a better position in the ranking) or the maximal deteriorations that alternatives can afford to maintain a target result (e.g., not losing their advantage over some other options). The use of a focus group with both experts and participants in the decision making process provided insights on how PFA can support: (i) the creation of arguments in favour or against the respective options under analysis, (ii) understanding of the results' sensitivity with respect to possible changes in the performances assigned to actions on different criteria, (iii) a better informed discussion about the results among the participants in the process, and (iv) the development of new/better alternatives.

DMAD

Wireless networks offer many advantages over wired local area networks such as scalability and mobility. Strategically deployed wireless networks can achieve multiple objectives like traffic offloading, network coverage, and indoor localization. To this end, various mathematical models and optimization algorithms have been proposed to find optimal deployments of access points (APs). However, wireless signals can be blocked by the human body, especially in crowded urban spaces. As a result, the real coverage of an on-site AP deployment may shrink to some degree and lead to unexpected dead spots (areas without wireless coverage). Dead spots are undesirable, since they degrade the user experience in network service continuity, on one hand, and, on the other hand paralyze some applications and services like tracking and monitoring when users are in these areas. Nevertheless, it is nontrivial for existing methods to analyze the impact of human beings on wireless coverage. Site surveys are too time consuming and labor intensive to conduct. It is also infeasible for simulation methods to predict the number of on-site people. In this article, we propose DMAD, a Data-driven Measuring of Wi-Fi Access point Deployment, which not only estimates potential dead spots of an on-site AP deployment but also quantifies their severity, using simple Wi-Fi data collected from the on-site deployment and shop profiles from the Internet. DMAD first classifies static devices and mobile devices with a decision-tree classifier. Then it locates mobile devices to grid-level locations based on shop popularities, wireless signal, and visit duration. Last, DMAD estimates the probability of dead spots for each grid during different time slots and derives their severity considering the probability and the number of potential users. The analysis of Wi-Fi data from static devices indicates that the Pearson Correlation Coefficient of wireless coverage status and the number of on-site people is over 0.7, which confirms that human beings may have a significant impact on wireless coverage. We also conduct extensive experiments in a large shopping mall in Shenzhen. The evaluation results demonstrate that DMAD can find around 70% of dead spots with a precision of over 70%.

Development and initial evaluation of a mobile application to help with mindfulness training and practice

Background and objectiveDifferent review articles support the usefulness and effectiveness of mindfulness techniques in health and wellbeing. In this paper we present a first prototype of a mobile application to help with the training and practice of mindfulness, taking into account the lacks detected in a previous literature review. Our aim was to measure acceptance and perceived quality, as well as gather data about app usage. Their dependence on demographic variables and the change in mindful level was also measured. Materials and methodsTwo versions of a new application were developed, “Mindfulness” and “Mindfulness Sci”. The application has been tested in two pilot studies: in traditional face-to-face mindfulness groups and in individual and independent use. Results3977 users were involved in this study: 26 in the first trial during an 8-week usage period and 3951 in the second trial during 17 months. In the first study, participants assessed the app with high scores. They considered it as a helping tool for mindfulness practice, user-friendly and with high quality of use. The positive perception was maintained after 8-weeks meditation workshops, and participants considered that its use could contribute to obtain benefits for mental and physical health. In the second study, we found rather weak associations between usage time and age, nationality and educational level. The mindful level showed a weak positive correlation with the session accomplished but slightly above the boundary of statistical significance (p-value=0.051). Videos and information stood out as the most accessed resources. ConclusionsUp to our knowledge, this is the first app developed with the help of health professionals in Spanish that could be used with a general aim, in health and wellbeing. The results are promising with a positive evaluation in face-to-face and independent use situations. Therefore, the number of potential users is enormous in a global worldwide context.

Strongly Conflict-Avoiding Codes with Weight Three

Strongly conflict-avoiding codes are used in the asynchronous multiple-access collision channel without feedback. The number of codewords in a strongly conflict-avoiding code is the number of potential users that can be supported in the system. In this paper, an improved upper bound on the size of strongly conflict-avoiding codes of length $$n$$n and weight three is obtained. This bound is further shown to be tight for some cases by direct constructions.

Operational Redistribution Model for a Large-Scale Bicycle-Sharing System

In recent years, bicycle-sharing systems (BSSs) have been getting more and more popular in many cities all over the world, particularly in developing countries. However, a significant operating problem was the imbalance that occurred in the distribution of bicycles, especially in large-scale BSSs during peak hours. This problem could significantly reduce the level of service and number of potential users. To improve the level of service of BSSs, the necessity of redistribution was analyzed, and an operational redistribution model (ORM) that could deal with large-scale redistribution was developed. The objective of the ORM was to minimize the generalized operation costs of BSSs, which were the penalty cost of unserved user demand and the cost of redistribution of bicycles. The overall system performance was analyzed under several scenarios. The results demonstrated that an ORM could effectively improve the level of service of a BSS and could provide a detailed work plan for each redistribution truck to implement. For redistribution in a large-scale BSS, the partition of subzones was important to achieve a high level of service with relatively low generalized costs. In addition, an optimal number of subzones could be found through the scenario-based optimization process.

Efficiency analysis of the health-care facilities of the UN Relief and Works Agency for Palestine Refugees in the Near East in Jordan: a retrospective, descriptive study

Background Through its health programme, the UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) is initiating reforms to transfer the decision-making capacity and responsibility to managers of health-care centres. To improve the efficiency of these reforms, we assessed the data by health-care facility and compared the facilities according to well established indicators of efficiency—namely, productivity and costs. Methods We undertook a retrospective, descriptive study of relevant data gathered during Jan 1, 2010, to Dec 31, 2010, from all 24 health-care centres of UNRWA in Jordan. We used a multidimensional approach to assess efficiency in which dimensions such as access, equity, use, and quality were included. Data were gathered for all these dimensions from several sources—departments of health, finance, procurement, and human resources at UNRWA. Estimates of population, health care, human resources, drugs and supplies, hospital admissions, and geographical access were obtained and, when possible, translated into monetary values. Data were compiled at UNRWA's health department and analysed with Microsoft Excel 2007 during Sept 1 to Nov 30, 2011. Findings The estimated overall expenditure on health care in 2010 was US$ 19·7 million, yielding a mean of $15·5 per beneficiary actively using the service. 60% of facility-attributed costs were for staff salaries, 27% for drugs and supplies, and 8% for hospital support. Expenditure per beneficiary on pharmaceutical drugs was $4·32 (range 3·17–8·38) and hospital care $1·35 (0·82–3·06). For every 10 000 refugees served by UNRWA's health-care centres, there was one medical officer. The number of contacts and consultations with UNRWA's health-care centres was 3·6 (2·4–8·0) and 1·16 (0·83–1·84), respectively, per patient. Efficiency, measured as daily consultations per day per medical officer, average daily contacts per nurse, midwife, and skilled birth attendants, total expenditure per contact, and drug expenditure per curative consultation, was 90 consultations (33–142) per day per medical officer, total expenditure per contact $4·28 (3·41–7·72), and drug expenditure per consultation $1·39 (0·88–1·71). Indicators of availability, service use, and efficiency showed large differences between facilities. 0·96 medical officers, ranging from 2·3 in Aqaba to 0·54 in Irbid Town, served 10 000 refugees. 2·4 nurses (including midwives), ranging from 1·4 in Amman Town to 7·0 in Waqqas, served 10 000 people. 3·4 skilled birth attendants (physicians, nurses, and midwives) served 10 000 refugees. Waqqas, Mashare, and Aqaba had more than eight skilled birth attendants per 10 000 people, whereas Irbid Town, Amman New Camp, and Amman Town had two per 10 000 population. Use of health-care facilities was highest at Jerash's health-care centre, with eight contacts (preventive and curative visits) per refugee, and lowest at Irbid Town and Amman Town health-care centres, neither of which had more than 2·5 contacts per person during the year. Productivity (consultations per medical officer per day) was lowest at Aqaba health-care centre with 33 consultations per medical officer; this number was almost four times higher in Msheirfieh and Jerash Camp health-care centres (142 and 140 consultations, respectively). Interpretation Resource availability, service use, and efficiency vary between the 24 health-care centres of UNRWA in Jordan. Overall, access to alternative public health-care providers (Ministry of Health and Royal Medical Services) seems to be the most important factor in determining efficiency of the health-care centres. For example, Jerash's health-care centre, which serves refugees from the Gaza Strip, occupied Palestinian territory, has the highest efficiency and serves the most refugees by contrast with Aqaba's health-care centre, which is attended by a small refugee population living far away from the largest towns and camps and has low efficiency. Although some centres' inefficiencies are unavoidable because of their location, UNRWA's health-care-system managers should reduce imbalances with an improved approach to resource allocation according to the actual number of people served and workload rather than the number of potential users. The data reported in this study cannot be easily compared with international data because UNRWA's health-care services are complementary to public health-care systems and mostly focused on primary health care. Funding UNRWA.

Problems with e-books: suggestions for publishers

Problems with e-books: suggestions for publishers

A simple fingerprinting scheme for large user groups

Digital fingerprinting is an emerging technology to protect multimedia data from piracy, where each distributed copy is labeled with unique identification information. In coded fingerprinting, each codeword of the anti-collusion code is used to represent a user's fingerprint. In real-world applications, the number of potential users can be very large and hence, the used anticollusion code should be easy to construct and have as many codewords as possible. This paper proposes a simple coded fingerprinting scheme, where the anticollusion code is constructed with an identity matrix. The main advantage of our scheme is its simplicity, as a large number of fingerprints can easily be generated to accommodate a large number of users. To improve collusion resistance, some transformations are performed on the original fingerprint in the embedding phase and the corresponding inverse transformations are performed on the extracted sequence in the detection phase.

Strongly Conflict-Avoiding Codes

Strongly conflict-avoiding codes (SCACs) are used in the slot-asynchronous multiple-access collision channel without feedback to guarantee that each active user can send at least one packet successfully in the worst case within a fixed period of time. The number of codewords in an SCAC is the number of potential users that can be supported. In this paper, a general upper bound on the size of SCAC is derived. We further improve the upper bound if the code has some special structure, called equi-difference, and we show this bound is asymptotically tight.