13 research outputs found
Perceptions and Practicalities for Private Machine Learning
data they and their partners hold while maintaining data subjects' privacy. In this thesis I show that private computation, such as private machine learning, can increase end-users' acceptance of data sharing practices, but not unconditionally. There are many factors that influence end-users' privacy perceptions in this space; including the number of organizations involved and the reciprocity of any data sharing practices. End-users emphasized the importance of detailing the purpose of a computation and clarifying that inputs to private computation are not shared across organizations. End-users also struggled with the notion of protections not being guaranteed 100\%, such as in statistical based schemes, thus demonstrating a need for a thorough understanding of the risk form attacks in such applications. When training a machine learning model on private data, it is critical to understand the conditions under which that data can be protected; and when it cannot. For instance, membership inference attacks aim to violate privacy protections by determining whether specific data was used to train a particular machine learning model.
Further, the successful transition of private machine learning theoretical research to practical use must account for gaps in achieving these properties that arise due to the realities of concrete implementations, threat models, and use cases; which is not currently the case
Arguments in favour of authentic and fabricated suicide notes as indistinguishable texts
Analyses of suicide notes have been conducted from varied perspectives in both linguistics and
psychology. Not only have these studies added considerable value to the study of suicide, but they
have also enriched the field of forensic linguistics. By analysing suicide notes, researchers are able
to speculate about the state of mind of a suicidal individual from a psychological perspective, as
well as gain insights into the characteristics of this genre from a linguistic perspective. Studies of
suicide notes that are most relevant to forensic linguistics are those that compare authentic and
fabricated suicide notes to determine whether these types of suicide notes may be distinguished
from one another. Although the literature on suicide notes includes multiple studies that consider
the differences between authentic and fabricated suicide notes, none seems to consider the fact that
there might not be distinct differences between these types of suicide notes. Past studies also do
not seem to consider that it might not be possible to determine whether a single suicide note is
authentic or not. The present study fills this gap by considering authentic and fabricated suicide
notes as indistinguishable texts. In this study, appraisal theory is used as the main theory of
linguistic analysis to prove that authentic and fabricated suicide notes do not have distinct
linguistic characteristics that can be used to differentiate them and that aiming to authenticate
suicide notes might be a very risky and problematic undertaking. The results indicate that based
on the theories and methods discussed in this thesis, it is not possible to successfully distinguish
between authentic and fabricated suicide notes. It appears that, overall, the suicide notes included
here would be more suited to analyses aimed at determining authorship identification or
verification than analyses aimed at authenticating suicide notes. Accordingly, the study contributes
not only to research concerned with the analysis of suicide notes but also to that concerned with
forensic linguistics. Furthermore, the study includes analyses of South African suicide notes, and
specifically Afrikaans suicide notes, which has not been attempted in previous research.Tshekatsheko ya mangwalo ao a ngwadilwego ke batho ba go ipolaya e dirilwe go tswa mahlakoreng ao a fapanego ka go bobedi dithutapolelo le dithutamahlale tsa menagano. Dinyakisiso tse ga se tsa oketsa boleng bjo bogolo fela go dinyakisiso ka ga ditiragalo tsa go ipolaya, eupsa di humisitse gape lekala la dithutapolelo tsa mabapi le batho bao ba ipolailego. Ka go sekaseka mangwalo ao a ngwadilwego ke batho ba go ipolaya, banyakisisi gape ba kgona go akanya mabapi le seemo sa monagano sa motho yo a ipolailego ka lehlakoreng la tsa menagano, gammogo le go hwetsa tsebo mabapi le dipharologantshi tsa mohuta wo wa sengwalwa ka lehlakoreng la dithutapolelo. Dinyakisiso tsa mabapi le mangwalo ao a ngwadilwego ke batho ba go ipolaya tseo di nyalelanago kudu le dithutapolelo tsa mabapi le batho ba go ipolaya ke tseo di bapetsago mangwalo a go ipolaya a makgonthe le a bofora go tseba ge eba mehuta ye ya mangwalo a batho ba go ipolaya a ka faralogantshwa le a mangwe. Le ge e le gore dingwalwa tsa mabapi le mangwalo ao a ngwadilwego ke batho ba go ipolaya di akaretsa dinyakisiso tse ntsi tseo di hlokometsego go fapana magareng ga mangwalo a batho ba go ipolaya a makgonthe le a bofora, ga go seo se hlokometsego ntlha ya gore go ka no se be le diphapano magareng ga mehuta ye ya mangwalo ao a ngwadilwego ke batho ba go ipolaya. Dinyakisiso tse di dirilwego mo nakong ye e fetilego le tsona di bonala di sa hlokomele ntlha ya gore go ka no se kgonagale go tseba ge eba lengwalo le tee leo le ngwadilwego ke motho wa go ipolaya ke la makgonthe goba aowa. Dinyakisiso tse di tlatsa sekgoba se ka go bona mangwalo ao a ngwadilwego ke batho ba go ipolaya a makgonthe le a bofora bjalo ka dingwalwa tseo di ka farologanywago. Ka mo dinyakisisong tse, teori ya go utolla tshekatsheko ya maikutlo e a somiswa bjalo ka teori ye kgolo ya go sekaseka polelo ka nepo ya go laetsa gore mangwalo ao a ngwadilwego ke batho ba go ipolaya a makgonthe le a bofora ga a na le dipharologantshi tse di bonagalago tse di ka somiswago go a farologanya le gore go ikemisetsa go dira gore mangwalo ao a ngwadilwego ke batho ba go ipolaya ke a makgonthe go ka ba mosomo o kotsi kudu le wo o nago le mathata. Dipoelo di laetsa gore go ya ka diteori le mekgwa ye e ahlaahlwago ka mo thesesing ye, ga go kgonagale go farologanya ka katlego phapano magareng ga mangwalo ao a ngwadilwego ke batho ba go ipolaya a makgonthe le a bofora. Go bonala gore, ka kakaretso, mangwalo ao a ngwadilwego ke batho ba go ipolaya ao a akareditswego ka mo a tla lokela kudu go tshekatsheko ye e ikemiseditsego go tseba motho yo a ngwadilego lengwalo la go ipolaya goba tiisetso go feta tshekatsheko ye e ikemiseditsego go tiisetsa gore mangwalo ao a mabapi le go ipolaya a ngwadilwe ke bomang. Ka se, dinyakisiso ga di tsenye letsogo fela go dinyakisiso tsa mabapi le tshekatsheko ya mangwalo ao a ngwadilwego ke batho ba go ipolaya, eupsa gape mabapi le dithutapolelo tsa mabapi le batho bao ba ipolailego. Godimo ga fao, dinyakisiso di akaretsa tshekatsheko ya mangwalo ao a ngwadilwego ke batho ba go ipolaya ka mo Afrika Borwa, gomme kudukudu mangwalo a go ngwalwa ka Seafrikantshe a batho bao ba ipolailego, e lego seo se sego sa dirwa ka dinyakisisong tse di fetilego.Ukuhlaziywa kwamanothi ezehlakalo zokuzikhunga/zokuzibulala kudala kwenziwa
ngokwemiqondo eyehlukahlukene ngezindlela ezimbili ngokwelingwistiki nangokwengqondo.
Izifundo zocwaningo azikhulisanga kuphela ukubaluleka kocwaningo olumayelana
nokuzikhunga kuphela, kodwa ziphinde zanothisa umkhakha weforensiki yelingwistiki.
Ngokuhlaziya amanothi amayelana nocwaningo, abacwaningi bayakwazi ukwenza umhlahlo
ngesimo somqondo womuntu ozikhungayo ngokomqondo wezengqondo, kanye nangokuzuza
ulwazi olumayelana nezimpawu zalo mkhakha ngokomqondo welingwistiki. Izimfundo
ezimayelana namanothi ashiywa ngabantu abazibulalayo ahlobene kakhulu neforensiki
yelingwistiki yilawo aqhathanisa amanothi okuzibulala oqobo nalawo angamanothimbumbulu,
ukucacisa kahle ukuthi mhlawumbe lezi zinhlobo zamanothi angahlukaniswa kwamanye. Yize
umbhalo wobuciko omayelana namanothi okuzibulala axuba izimfundo zocwaningo eziningi
ezigxile kwimehluko ephakathi kwamanothi okuzibulala oqobo nalawo okuzakhela/ambumbulu,
akhekho obheka udaba lokuthi kungahle kungabi khona umehluko ogqamile phakathi kwalezi
zinhlobo zamanothi okuzibulala. Izimfundo zocwaningo zesikhathi esedlule nazo azilubheki
udaba lokuthi angekhe kwenzeka ukuthi kutholakale ukuthi mhlawumbe inothi lokuzibulala
ngabe elangempela noma yinothimbumbulu. Isifundo samanje sivala lesi sikhala ngokuthatha
amanothi angempela namanothimbumbulu njengemibhalo engahlukaniseki. Kulesi sifundo
socwaningo, ithiyori yokuhlola isetshenziswe njengethiyori eyinsika yokuhlaziya ilingwistiki
ukukhombisa ukuthi amanothi okuzibulala angempela nalawo okuzakhela akanazo izimpawu
ezibaphawulekayo ezingasetshenziswa ukuwehlukanisa kanti lokho kuqonde ukuqinisekisa
ukuthi amanothi okuzibulala kungenzeka abe wumsebenzi onobungozi obukhulu kanye nenkinga
enkulu. Imiphumela ikhombisa ukuthi ngokwamathiyori nangezindlela ezixoxwe kule thiyori,
kunzima ukuphumelela uthole umehluko phakathi mwamanothi angempela nalawo ambumbulu.
Ngaphezu kwalokho, kuyakhombisa ukuthi, amanothi okuzibulala aqukethwe lapha
azohambisana kakhulu nolwazi oluhlaziyiwe oluqonde ukuthola umnini wenothi noma
ukuqinisekisa kunolwazi oluhlaziyiwe oluhlose ukuqinisekisa umbhali wamanothi okuzibulala.
Ngokosiko lwakhona, isifundo asifakanga kuphela igalelo kucwaningo kuphela ngokuhlaziya
amanothi okuzibulala, kanti lokho futhi kumayelana neforensiki yelingwistiki. Ngaphezu
kwalokho, ucwaningo luqukethe ulwazi oluhlaziyiwe lwamanothi okuzibulala eNingizimu
Afrika, ikakhulu amanothi okuzibulala abhalwe ngesiBhunu, angakazwe alokothwe kucwaningo
lwesikhathi esedlule.Linguistics and Modern LanguagesPh. D. (Forensic Linguistics
DNA replication and repair in microcephalic dwarfism
Human height varies greatly between and within populations, and some individuals
fall at the extreme ends of this wide spectrum. At the lower end of this distribution,
individuals demonstrating extreme prenatal-onset reduction in body size and brain growth
are classified as having microcephalic primordial dwarfism (MPD), which encompasses a
group of rare single-gene disorders, usually inherited in an autosomal recessive manner. The
human brain is particularly susceptible to perturbation during embryonic development, and
the inability of neural progenitor cells to complete timely proliferation is thought to be an
important contributor to the observed reduction in cerebral cortical size.
Studying genes whose disruption leads to severe reduction in human growth can
facilitate our understanding of the molecular pathways underlying cell proliferation and
organism development. Mutations in many identified MPD genes result in the extended
length of the cell cycle and impaired cell division by affecting essential cellular processes,
such as DNA replication, DNA damage response (DDR) signalling, centriole biogenesis and
mRNA splicing. The ability of cells to efficiently copy DNA and maintain the stability of their
genome by promoting error-free repair of various types of DNA damage caused by
endogenous and exogenous sources is particularly important for the timely cell cycle
completion and cell survival. Therefore, it is not surprising that many MPD genes play a role
in DNA replication, DDR and DNA repair.
In this thesis, three DNA replication and DDR genes, mutated in MPD, are
investigated. DNA2, encoding an ATP-dependent helicase/nuclease, was found to be
mutated in four MPD patients. Experiments to confirm pathogenicity of the identified
mutations indicated that they are likely to cause disease by affecting DNA2 transcript splicing
and its enzymatic activities. My work described here also analyses the cellular role of TRAIP,
an E3 ubiquitin ligase, which was linked to MPD by our laboratory (Harley et al., 2016). Cell
experiments using TRAIP knockout cell lines, generated with CRISPR/Cas9 genome editing
technology, demonstrated the requirement for TRAIP and its E3 ligase activity in DDR and
repair of camptothecin (CPT)-induced DNA damage. Additionally, TRAIP was important for
cell survival after mitomycin C (MMC)-induced DNA damage, but no epistasis with the
Fanconi Anaemia (FA) interstrand crosslink (ICL) repair pathway was demonstrated,
indicating an additive effect of TRAIP and FA-ICL pathways to repair these DNA lesions.
Finally, generation of a mouse model of MPD caused by mutations in DONSON, a
novel replication fork protection factor (Reynolds et al., 2017), is described in this thesis.
DONSON MPD mice, harbouring the mouse equivalent of one of the human MPD missense
mutations, showed embryonic lethality, with homozygous mutant embryos significantly
smaller than their littermates and exhibiting limb abnormalities. Increased levels of
spontaneous DNA damage were observed in mouse embryonic fibroblasts established from
these embryos, mimicking the cellular phenotype of human DONSON deficiency.
In summary, this thesis advances our knowledge of the cellular and developmental
roles of MPD genes TRAIP, DNA2, and DONSON, that encode proteins maintaining genome
stability
Improving Security and Privacy in Large-Scale RFID Systems
Radio Frequency Identification (RFID) technologies lay in the very heart of Internet of Things (IoT), in which every physical objects are tagged and identified in an internet-like structure. High performance and privacy-preserving interrogations of individual tags, generally called private tag authentication, is crucial for effective monitoring and management of a large number of objects with RFID tags. An RFID system consists of RF readers and RF tags. RF tags are attached to objects, and used as a unique identifier of the objects. RFID technologies enable a number of business and personal applications, and smooth the way for physical transactions in the real world, such as supply chain management, transportation payment, animal identification, warehouse operations, and more. Though bringing great productivity gains, RFID systems may cause new security and privacy threats to individuals or organizations, which have become a major obstacle for their wide adaptions. Therefore, it is important to address the security and privacy issues in RFID systems. In this dissertation, we investigate two important security and privacy issues for large-scale RFID systems. First, we discuss the private tag authentication problems. In a singulation process, an RF reader first sends a query and energizes an RF tag, and then the tag replies its ID or data to the reader. As the tag\u27s ID itself is sensitive information, the reply from tags must be protected against various threats, such as eavesdropping and compromise attacks, where tags are physically tampered and the keys associated with compromised tags are disclosed to adversaries. Fast and secure object identification, generally called private tag authentication, is critical to efficiently monitor and manage a large number of objects with Radio Frequency Identification (RFID) technologies. In a singulation process, an RF reader queries an RF tag, and then the tag replies its ID or data to the reader. Since the tags ID itself is private information, the reply must be protected against various threats, such as eavesdropping and com-promised attacks, where tags are physically tampered and the keys associated with compromised tags are disclosed to adversaries. Hence a large amount of efforts have been made to protect tags replies with low-cost operations, e.g., the XOR operation and 16-bit pseudo random functions (PRFs). In the primitive solution, a tag sends a hashed ID, instead of its real ID, to a reader, and then, the reader searches the corresponding entry in the back-end server. While this approach defends tags replies against various attacks, the authentication speed is of 0(N), where N is the number of tags in the system. Hence, such a straightforward approach is not practical for large-scale RFID systems. In order to efficiently and securely read tags content, private authentication protocols with structured key management have been proposed. In these schemes, each tag has its unique key and a set of groups keys. Groups keys are shared by several tags and used to confine the search space of a unique key. With efficient data structures, the tag authentication completes within 0(log k N). How-ever, private authentication protocols with structured key management unfortunately reduce the degree of privacy, should some tags in the system be compromised. This is because group keys are shared by several tags, and physical tampering of some tags makes the other tags less anonymous. How to remedy this issue is equivalent to reducing the probability that two tags share common group keys (hence after we refer to it as the correlation probability). The introduction of random walking over a data structure, e.g., randomized tree-walking and randomized skip-lists, significantly reduces the correlation probability. Nevertheless, two tags are still correlated should they have same groups keys at all the levels of in a balanced tree or skip lists. In our study, we design a private tag authentication protocol, namely Randomized Skip Graphs-Based Authentication (RSGA), in which unique and group keys are maintained with a skip graph. The RSGA achieves lower correlation probability than the existing scheme while maintaining the same authentication speed as the tree structure. Second, we discuss the fast and secure grouping problems. In the large-scale RFID systems, categorization and grouping of individual items with RF tags are critical for efficient object monitoring and management. For example, when tags belonging to the same group share a common group ID, the reader can transmit the same data simultaneously to the group ID, and it is possible to save considerably the communication overhead as compared with the conventional unicast transmission. To this end, Liu et al. recently propose a set of tag grouping protocols, which enables multicast-like communications for simultaneous data access and distribution to the tags in the same group. In the reality, not only the performance issue, but also security and privacy-preserving mechanisms in RFID protocols are important for protecting the assets of individuals and organizations. Although a number of works have been done for protecting tag\u27s privacy, to the best of our knowledge, the problem of private tag grouping is yet to be addressed. To address the problem of private tag grouping in a large-scale RFID system, we first formulate the problem of private tag grouping and define the privacy model based on the random oracle model. As a baseline protocol, we design a private traditional polling grouping (PrivTPG) protocol based on traditional tag polling protocol. Since PrivTPG is a straightforward approach, it can take a long time. Hence, based on the idea of broadcasting group IDs, we propose a private enhanced polling grouping (PrivEPG) protocol. To further improve the efficiency of tag grouping, we propose a private Bloom filter-based grouping (PrivBFG) protocol. These protocols broadcast unencrypted group IDs. Therefore, we propose a private Cuckoo filter-based polling grouping (PrivCFG) protocol, which is a more secure protocol using a data structure called a cuckoo filter. Then, the protocol-level tag\u27s privacy of the proposed PrivTPG, PrivEPG, PrivBFG, and PrivCFG is proven by random oracles. In addition, computer simulations are conducted to evaluate the efficiency of the proposed protocols with different configurations.首都大学東京, 2018-03-25, 修士(工学)首都大学東
Security protocols for EPC class-1 Gen-2 RFID multi-tag systems
The objective of the research is to develop security protocols for EPC C1G2 RFID Passive Tags in the areas of ownership transfer and grouping proof
Combining SOA and BPM Technologies for Cross-System Process Automation
This paper summarizes the results of an industry case study that introduced a cross-system business process automation solution based on a combination of SOA and BPM standard technologies (i.e., BPMN, BPEL, WSDL). Besides discussing major weaknesses of the existing, custom-built, solution and comparing them against experiences with the developed prototype, the paper presents a course of action for transforming the current solution into the proposed solution. This includes a general approach, consisting of four distinct steps, as well as specific action items that are to be performed for every step. The discussion also covers language and tool support and challenges arising from the transformation