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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Study on False Information Injection Attack on Dynamic State Estimation in Multi-Sensor Systems

Lu, Jingyang 01 January 2015 (has links)
In this thesis, the impact of false information injection is investigated for linear dynamic systems with multiple sensors. It is assumed that the Kalman filter system is unaware of the existence of false information and the adversary is trying to maximize the negative effect of the false information on the Kalman filter's estimation performance. First, a brief introduction to the Kalman filter is shown in the thesis. We mathematically characterize the false information attack under different conditions. For the adversary, many closed-form results for the optimal attack strategies that maximize the Kalman filter's estimation error are theoretically derived. It is shown that by choosing the optimal correlation coefficients among the bias noises and allocating power optimally among sensors, the adversary could significantly increase the Kalman filter's estimation errors. To be concrete, a target tracking system is used as an example in the thesis. From the adversary's point of view, the best attack strategies are obtained under different scenarios, including a single-sensor system with both position and velocity measurements, and a multi-sensor system with position and velocity measurements. Under a constraint on the total power of the injected bias noises, the optimal solutions are solved from two perspectives: trace and determinant of the mean squared error matrix. Numerical results are also provided in order to illustrate the negative effect which the proposed attack strategies could inflict on the Kalman filter.
2

Designing a Media Literacy Online Educational Platform for Retired Adults

Tsai, Ching-Tzu 23 August 2022 (has links)
No description available.
3

On the Detection of False Information: From Rumors to Fake News

Ghanem, Bilal Hisham Hasan 10 January 2021 (has links)
[ES] En tiempos recientes, el desarrollo de las redes sociales y de las agencias de noticias han traído nuevos retos y amenazas a la web. Estas amenazas han llamado la atención de la comunidad investigadora en Procesamiento del Lenguaje Natural (PLN) ya que están contaminando las plataformas de redes sociales. Un ejemplo de amenaza serían las noticias falsas, en las que los usuarios difunden y comparten información falsa, inexacta o engañosa. La información falsa no se limita a la información verificable, sino que también incluye información que se utiliza con fines nocivos. Además, uno de los desafíos a los que se enfrentan los investigadores es la gran cantidad de usuarios en las plataformas de redes sociales, donde detectar a los difusores de información falsa no es tarea fácil. Los trabajos previos que se han propuesto para limitar o estudiar el tema de la detección de información falsa se han centrado en comprender el lenguaje de la información falsa desde una perspectiva lingüística. En el caso de información verificable, estos enfoques se han propuesto en un entorno monolingüe. Además, apenas se ha investigado la detección de las fuentes o los difusores de información falsa en las redes sociales. En esta tesis estudiamos la información falsa desde varias perspectivas. En primer lugar, dado que los trabajos anteriores se centraron en el estudio de la información falsa en un entorno monolingüe, en esta tesis estudiamos la información falsa en un entorno multilingüe. Proponemos diferentes enfoques multilingües y los comparamos con un conjunto de baselines monolingües. Además, proporcionamos estudios sistemáticos para los resultados de la evaluación de nuestros enfoques para una mejor comprensión. En segundo lugar, hemos notado que el papel de la información afectiva no se ha investigado en profundidad. Por lo tanto, la segunda parte de nuestro trabajo de investigación estudia el papel de la información afectiva en la información falsa y muestra cómo los autores de contenido falso la emplean para manipular al lector. Aquí, investigamos varios tipos de información falsa para comprender la correlación entre la información afectiva y cada tipo (Propaganda, Trucos / Engaños, Clickbait y Sátira). Por último, aunque no menos importante, en un intento de limitar su propagación, también abordamos el problema de los difusores de información falsa en las redes sociales. En esta dirección de la investigación, nos enfocamos en explotar varias características basadas en texto extraídas de los mensajes de perfiles en línea de tales difusores. Estudiamos diferentes conjuntos de características que pueden tener el potencial de ayudar a discriminar entre difusores de información falsa y verificadores de hechos. / [CA] En temps recents, el desenvolupament de les xarxes socials i de les agències de notícies han portat nous reptes i amenaces a la web. Aquestes amenaces han cridat l'atenció de la comunitat investigadora en Processament de Llenguatge Natural (PLN) ja que estan contaminant les plataformes de xarxes socials. Un exemple d'amenaça serien les notícies falses, en què els usuaris difonen i comparteixen informació falsa, inexacta o enganyosa. La informació falsa no es limita a la informació verificable, sinó que també inclou informació que s'utilitza amb fins nocius. A més, un dels desafiaments als quals s'enfronten els investigadors és la gran quantitat d'usuaris en les plataformes de xarxes socials, on detectar els difusors d'informació falsa no és tasca fàcil. Els treballs previs que s'han proposat per limitar o estudiar el tema de la detecció d'informació falsa s'han centrat en comprendre el llenguatge de la informació falsa des d'una perspectiva lingüística. En el cas d'informació verificable, aquests enfocaments s'han proposat en un entorn monolingüe. A més, gairebé no s'ha investigat la detecció de les fonts o els difusors d'informació falsa a les xarxes socials. En aquesta tesi estudiem la informació falsa des de diverses perspectives. En primer lloc, atès que els treballs anteriors es van centrar en l'estudi de la informació falsa en un entorn monolingüe, en aquesta tesi estudiem la informació falsa en un entorn multilingüe. Proposem diferents enfocaments multilingües i els comparem amb un conjunt de baselines monolingües. A més, proporcionem estudis sistemàtics per als resultats de l'avaluació dels nostres enfocaments per a una millor comprensió. En segon lloc, hem notat que el paper de la informació afectiva no s'ha investigat en profunditat. Per tant, la segona part del nostre treball de recerca estudia el paper de la informació afectiva en la informació falsa i mostra com els autors de contingut fals l'empren per manipular el lector. Aquí, investiguem diversos tipus d'informació falsa per comprendre la correlació entre la informació afectiva i cada tipus (Propaganda, Trucs / Enganys, Clickbait i Sàtira). Finalment, però no menys important, en un intent de limitar la seva propagació, també abordem el problema dels difusors d'informació falsa a les xarxes socials. En aquesta direcció de la investigació, ens enfoquem en explotar diverses característiques basades en text extretes dels missatges de perfils en línia de tals difusors. Estudiem diferents conjunts de característiques que poden tenir el potencial d'ajudar a discriminar entre difusors d'informació falsa i verificadors de fets. / [EN] In the recent years, the development of social media and online news agencies has brought several challenges and threats to the Web. These threats have taken the attention of the Natural Language Processing (NLP) research community as they are polluting the online social media platforms. One of the examples of these threats is false information, in which false, inaccurate, or deceptive information is spread and shared by online users. False information is not limited to verifiable information, but it also involves information that is used for harmful purposes. Also, one of the challenges that researchers have to face is the massive number of users in social media platforms, where detecting false information spreaders is not an easy job. Previous work that has been proposed for limiting or studying the issue of detecting false information has focused on understanding the language of false information from a linguistic perspective. In the case of verifiable information, approaches have been proposed in a monolingual setting. Moreover, detecting the sources or the spreaders of false information in social media has not been investigated much. In this thesis we study false information from several aspects. First, since previous work focused on studying false information in a monolingual setting, in this thesis we study false information in a cross-lingual one. We propose different cross-lingual approaches and we compare them to a set of monolingual baselines. Also, we provide systematic studies for the evaluation results of our approaches for better understanding. Second, we noticed that the role of affective information was not investigated in depth. Therefore, the second part of our research work studies the role of the affective information in false information and shows how the authors of false content use it to manipulate the reader. Here, we investigate several types of false information to understand the correlation between affective information and each type (Propaganda, Hoax, Clickbait, Rumor, and Satire). Last but not least, in an attempt to limit its spread, we also address the problem of detecting false information spreaders in social media. In this research direction, we focus on exploiting several text-based features extracted from the online profile messages of those spreaders. We study different feature sets that can have the potential to help to identify false information spreaders from fact checkers. / Ghanem, BHH. (2020). On the Detection of False Information: From Rumors to Fake News [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/158570 / TESIS
4

Kan jag lita på det här? : En undersökning om spridning av falsk information i sociala medier.

Sewon, Isak January 2023 (has links)
Today's media landscape is larger and more diverse than ever before. Individuals are fedwith news and information from many different types of media. When competition ishigh, media actors need to stand out to be noticed, sometimes to the extent that the truthis omitted or embellished. The purpose of this essay is to examine the consequences ofthe spread of false information on social media. The material of the essay consists of 25Swedish videoclips from YouTube and is intended to investigate how well the videoportals (headlines & thumbnails) correspond to the actual content of the videos. Themethod used in the essay is a quantitative coding of these videoclips and a multimodalanalysis from a selection of these coded video clips. To fulfill the purpose of the essay,theories and concepts such as misinformation and disinformation, filter bubbles, andselective exposure theory are used. The results of the study showed that many videoportals do not correspond at all to the content that the clip possesses. They oftenexaggerate or add details that make the video clip stand out more or appear moreinteresting for the audience to engage with. The consequences of false information spreadon social media can be many. For example, it can contribute to somewhat distortedworldviews. If individuals in a society are fed with incorrect information, it becomes moredifficult to get a fair picture of the world. It can also become normalized that thingswritten on social media are often not true, which leads to it becoming commonplace tobuy into small lies and not trust the information and news consumed online.
5

Nytt men inte fejkat om fake news : En studie om det svenska civilsamhällets mobilisering mot fake news

Einarsdotter, Carina January 2018 (has links)
Fake news har fått ett starkt fäste i sociala medier och är ett växande problem – för individen såväl som för samhället. Grundläggande teorier om beslutsfattande, samarbete, kommunikation och marknader bygger alla på en bärande idé om att information är sann, precis och samvetsgrann. Det finns starka både ideologiska och ekonomiska motiv bakom spridningen av felaktiga fakta, falska berättelser, lögner och konspirationsteorier. Det råder en uttalad oro över effekten på politiska val och den demokratiska utvecklingen, men också farhågor om andra potentiella negativa konsekvenser, från ökande cynism och apati till hetsande extremism. Åtgärder för att minska utbredningen diskuteras, i litteraturen framträder fyra olika huvudformer: statliga interventioner, självpåtagna begränsningar/plattformspolicys, teknologiska lösningar och utbildning i källkritik. Civilsamhällets roll i begränsningen av spridningen är, såvitt kunnat överblickas, tidigare inte studerad. Denna explorativa studie syftar till att öka kännedomen om det svenska civilsamhällets mobilisering mot fake news. De aktörer som identifierats i studien är för civilsamhället karaktäristiska frivilligorganisationer som dels agerat självständigt, dels i samarbete med offentlig sektor och/eller näringslivet. Samtliga aktörer har haft mobiliseringen mot fake news som en biuppgift, det vill säga det har inte varit deras enda eller deras huvuduppgift. I studien har fem huvudstrategier framträtt i mobiliseringen mot fake news: grundläggande utbildning och undervisning, allmänbildande kompetenshöjning, understödjande, skapa debatt och påverkansarbete. Angreppssättet har varit kvalitativ innehållsanalys. / Fake news has gained a strong foothold in social media and is a growing problem - for the individual as well as for the whole society. Basic theories of decision making, cooperation, communication and markets are all based on the idea that information is true, accurate and conscientious. There are strong both ideological and economic motives behind the spread of false facts, false stories, lies and conspiracy theories. There is a deep concern about the effect this may have on political elections and democratic developments, but also concerns about other potential negative consequences, from increasing cynicism and apathy to instigative extremism. Measures to reduce dissemination are discussed and the literature shows four different main forms: government intervention, self-imposed measures/platform policies, technology solutions and source criticism training. The role of civil society in limiting the spread is, as far as it could be established by the author, not studied previously. This exploratory study aims to raise awareness about the Swedish civil society's mobilization against fake news. The actors identified in the study are civil society voluntary organizations who acted independently, or in cooperation with the public sector and/or business sector. All actors have mobilized against fake news as a secondary task, that is, it has not been their sole or their main task. In the study, five main strategies have emerged in the mobilization: basic education and training, general education enhancement, supporting, creating debate and impact work. The methodological approach in this study has been qualitative content analysis.
6

Falsk information på webben : Med fokus på ideologisk polarisering som underliggande orsak

Kristoffersson, Robert January 2018 (has links)
Detta kandidatarbete fokuserar på ideologisk polarisering som orsak till den stora mängden falsk information som har spridits den senaste tiden. Jag undersöker hur selektiv exponering och filterbubblor har bidragit till att den ideologiska polariseringen har följt med in på webben, och hur nyhetsfeed har agerat som en grogrund för detta. I ett försök till att minska den ideologiska polariseringen i nyhetsfeed skapade jag en webbapplikation i form av ett nyhetsfeed med nyhetsartiklar som med hjälp av algoritmer låter användaren se utanför sin filterbubbla för att balansera nyhetsfeedet mellan flera olika nyhetskällor. / This bachelor thesis focuses on ideological polarization as cause for the vast amount of false information that have been spread lately. I examine how selective exposure and filter bubbles have contributed to the ideological polarization that followed into the web, and how newsfeed have been acting as a breeding ground for this. In an attempt to reduce the ideological polarization in newsfeed I created a web application in the form of a newsfeed with news articles, that with the help of algorithms let the user see beyond its filter bubble to balance the newsfeed between different news sources.
7

Stop spreading the news! : How disinformation spreads on social media and what politicians are doing about it

Hjorth, Patric January 2020 (has links)
Following the rise of social media, the world has found itself in a hyperconnected state. Through the press of a button, it is today possible to reach every corner of the world. This has brought opportunities for freedom and liberation, but in the past years it has also become a danger for these ideas. The rise of disinformation has been declared a major threat to democracy and our society by several major institutions, one of them being the European Union. They have also made it clear that the tech companies, through whose products disinformation primarily spreads, not only inadequately prevent it, but also question if they have enough incentive to do so. The executive branch of the EU, the European Commission, has therefore put forth an action plan in which they outline their work going forward in mitigating the crisis. Comparing with previous research on the vital parts of disinformation, there are heavy indications that the EU’s work will focus on reactionary measures; discovery and sharing of data on ongoing disinformation campaigns between neighbouring and Member States, as well as societal media literacy efforts. For now, due to what seems to be a fear of over-regulating freedom of expression, the responsibility to battle creation and spread is left to the Code of Practice on Disinformation, a plan created by tech companies that hold the platforms that are center in the spread of disinformation. After a first yearassessment, the EU indicates that the results of this Code of Practice is unsatisfactory, and further action might be needed. / Med uppkomsten av sociala medier så befinner sig världen nu i ett hyperuppkopplat tillstånd. Genom ett simpelt knapptryck är det idag möjligt att nå hela världen. Med detta har vi sett möjligheter till en förhöjd frihet, men under de senaste åren finns det också exempel på när just idéer som dessa har satts under hård press. Ökningen av desinformation har förklarats ett stort hot mot demokrati och dagens samhälle av flera stora institutioner, en av dem den Europeiska Unionen. De har gjort tydligt att stora teknikbolag, genom vilkas produkter desinformation i synnerhet sprids, inte bara gör för lite för att förhindra det, men också ifrågasätter ifall de har tillräckligt med incitament för att göra det. EU:s verkställande gren, Europeiska Kommissionen, har därför satt fram en handlingsplan där de redogör för sitt arbete för att hantera krisen. I en jämförelse med tidigare forskning om de mest vitala delarna av desinformation så finns det tunga indikationer att EU:s arbete kommer att fokusera på reaktionära åtgärder: upptäckande och delning av data mellan grannländer och medlemsstater om pågående desinformationskampanjer, samt ansträngningar för samhällskunskap så som källkritik. I vad som verkar vara en rädsla för överreglering av yttrandefrihet lämnas ansvaret för bekämpningen av skapande och spridning till en desinformationspraxis skapad av de teknikföretag som har de plattformar som är centrala i spridningen av desinformation. Efter en första årsutvärdering indikerar dock EU att resultaten dittills ej är tillfredsställande, och att ytterligare åtgärder kan vara nödvändiga.
8

金融犯罪之訴訟策略 —以我國證券交易法操縱市場案件為中心 / The Litigation Strategy for Financial Crime —Focus on The Cases of Market Manipulation of Securities Exchange Act in Taiwan

莊凱如 Unknown Date (has links)
金融犯罪近年來日益受學者與實務界之重視,而我國證券交易 法既以「發展國民經濟、保障投資」為目的,證券市場是否依自然 供需法則自由運作,而不受人為操縱行為破壞價格決定機制,顯得 至為重要。 我國證券交易法明文禁止操縱市場行為,違反者除民事損害賠 償責任外,尚有刑事處罰,且刑度非輕。操縱市場雖屬於相對抽象 之一種禁止類型,但法院實務上已經累積為數不少之判決,然而因 案件內容繁雜、法條構成要件不夠明確......等因素,造成法律見解難 以統一之現象,進而使得辯護工作難度增加。 本文擬從比較法上,參考外國法對操縱市場行為禁止之類型及 方式,檢視我國證券交易法中關於操縱市場之立法過程與構成要 件,並蒐集大量法院判決,整理分析被告提出之各式抗辯,回顧法 院判決中之見解、判斷,期待能更深入問題之核心,裨對實務工作 者能有所助益。 / Financial crimes are increasingly valued by academics and practitioners in recent years. Securities and Exchange Act in Taiwan is securities market operate freely in accordance with the law of natural supply and demand without undermining the mechanism of price determination by human manipulation so important. Securities and Exchange Act in Taiwan expressly prohibited for market manipulation and penalize who breach of regulation. They must bear civil liability for damages and seriously criminal penalties. Although market manipulation may be very abstract sometimes, court practice has accumulated a large number of judgments. However, it’s still a big challenge for attorneys due to the different opinions in practice. The relevant provisions of this order the United States, England and China on different types of legislation about manipulation, in order to find the difference of among the Securities and Exchange Law of Taiwan, as a reference to amend acts of manipulation. By studying cases selected our Court and trying to analyze how the various defenses affect the court decision.
9

興櫃股票適用我國證券交易法反市場操縱條款之研究 / A study of adapting the anti-manipulation provisions to taiwan emerging stock market

陳永明, Chen, Yung Ming Unknown Date (has links)
我國興櫃股票之交易方式係由推薦證券商(即興櫃股票之造市商)之報價主導交易進行,屬於報價驅動(Quote-driven)之交易方式,與我國上櫃股票採取「等價交易」及上市股票採取「競價交易」等均屬委託單驅動(Order-driven)之交易方式迥然不同。 按我國證券交易法第155條第2項準用同條第1項規定之適用結果,「於證券商營業處所買賣有價證券」者,仍應有第1項所揭反市場操縱條款之適用。惟有關興櫃股票交易在成交對象之選擇、成交順序、成交價格決定,乃至於成交後之給付結算作業方式等,均與我國現行上市(櫃)股票之交易及交割方式具有明顯之差異,致應如何適用證券交易法反市場操縱條款之規定,乃成疑義。 本文鑒於興櫃股票市場規模已呈穩定成長之勢,不難想像興櫃股票交易與市場操縱行為之間終將有擦出爭議火花之時,故以比較法學研究之觀點,歸納並分析興櫃股票與上市(櫃)股票交易方式之差異及其癥結所在。另蒐集瀏覽世界各國主要證券市場之交易規制,包括美國OTCBB市場、歐陸Alternext市場及英國AIM市場,分析其他採用報價驅動交易模式之先進市場當中有關造市商義務之規範,以掌握造市商義務之核心意涵。進而以造市商義務範圍及報價驅動市場之交易特徵為基礎,逐一檢測興櫃股票適用我國證券交易法所揭「違約不交割」、「相對委託」、「連續交易」、「沖洗買賣」、「散布流言或不實資料」及「其他直接或間接操縱市場」等各款反市場操縱條款規定可能引發之爭議,並提出本文意見。 / The trading mechanism of Taiwan Emerging Stock is based on quote-driven model, which is very different from the order-driven model of the Taiwan OTC securities market and Taiwan Stock Exchange market. By the Taiwan Securities and Exchange Act Article 155 paragraph 2 permitted that paragraph 1, the anti-market manipulation provisions, shall apply mutatis mutandis to securities transactions conducted on the over-the-counter markets. However, lots of Taiwan Emerging stock trading rules such as allowing the participants to choose their counterparty, the matching sequence rules, the price decision rules, and even the rules of payment and settlement practices after transaction, all have significantly differences between those of Taiwan Emerging stock market and listed stock market. Therefore, how should Taiwan Emerging stock apply to the Securities Exchange Act under the terms of the anti-market manipulation is into doubt. Taiwan Emerging stock market has shown a steady growth trend, hence, it is easy to imagine that Taiwan Emerging stock trading and market manipulation issues will eventually rise to controversy. This thesis is to study from the point of view of comparative law, by means of analyzing the emerging stock markets of the advanced countries, including the U.S. OTCBB market, the European Alternext market and the UK AIM market, to conclude the crux of the difference between the quote-driven and order-driven market models. Then, to understand the characteristics and core obligation of the market maker under quote-driven market model, furthermore, to detect the disputes may lead for adapting the anti-manipulation provisions to Taiwan Emerging stock, including the terms of "breach of contract non-deliverable", "improper matched orders ", "continuous trading", "wash sale", "spreading rumors or false information" and other direct or indirect behavior of manipulation". And this thesis proposed its discovery at the end.

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