Privacy-safe network trace sharing via secure queries

Privacy concerns relating to sharing network traces have traditionally been handled via sanitization, which includes removal of sensitive data and IP address anonymization. We argue that sanitization is a poor solution for data sharing that offers insufficient research utility to users and poor privacy guarantees to data providers. We claim that a better balance in the utility/privacy tradeoff, inherent to network data sharing, can be achieved via a new paradigm we propose: secure queries. In this paradigm, a data owner publishes a query language and an online portal, allowing researchers to submit sets of queries to be run on data. Only certain operations are allowed on certain data fields, and in specific contexts. Query restriction is achieved via the provider’s privacy policy, and enforced by the language’s interpreter. Query results, returned to researchers, consist of aggregate information such as counts, histograms, distributions, etc. and not of individual packets. We discuss why secure queries provide higher privacy guarantees and higher research utility than sanitization, and present a design of the secure query language and a privacy policy

Understanding DNS Query Composition at B-Root

The Domain Name System (DNS) is part of critical internet infrastructure, as DNS is invoked whenever a remote server is accessed (an URL is visited, an API request is made, etc.) by any application. DNS queries are served in hierarchical manner, with most queries served locally from cached data, and a small fraction propagating to the top of the hierarchy - DNS root name servers. Our research aims to provide a comprehensive, longitudinal characterization of DNS queries received at B-Root over ten years. We sampled and analyzed a 28-billion-query large dataset from the ten annual Day in the Life of the Internet (DITL) experiments from 2013 through 2022. We sought to identify and quantify unexpected DNS queries, establish longitudinal trends, and compare our findings with published results of others. We found that unexpected query traffic increased from 39.57% in 2013 to 67.91% in 2022, with 36.55% of queries being priming queries. We also observed growth and decline of Chromium-initiated, random DNS queries. Finally, we analyzed the largest DNS query senders and established that most of their traffic consists of unexpected queries.Comment: 20 pages with 18 figures and 1 table. Published and presented at the 2022 IEEE/ACM International Conference on Big Data Computing, Applications and Technologies (BDCAT

Quality characteristics of ‘Pasta-Filata’ Serbian Kačkavalj cheese and regulatory compliance assessment

The purpose of this study was to investigate the chemical, proteolysis, microbiological, colour and textural characteristics of Serbian Kačkavalj cheese in order to determine the variability degree between cheeses, compare their properties to other similar ‘Pasta Filata’ cheeses and to determine if they comply to the regulative requirements. A broad range of variations of cheese characteristics was found among Kačkavalj cheeses. The composition showed high variations: dry matter ranged from 51.52 % to 58.71 %; fat from 20.00 % to 29.50 %; fat in dry matter from 36.08 % to 55.96 %; NaCl from 0.93 % to 3.69 %; total protein from 23.25 % to 30.79 %. The proteolysis parameters in Kačkavalj cheeses differed significantly. The colour evaluation showed significant differences in a* and b* values, however in L* values there were no significant differences (p>0.05). The traditional Kačkavalj cheese represents the part of national heritage; thus, the comprehensive characterization was conducted to investigate quality variations between Serbian Kačkavalj cheeses. The study identified that term Kačkavalj is used despite some cheeses are not fully compliant with the National Standard. The control of fulfilling the requirements of the National Standard should be improved, as well as raising awareness and prevention of inadequate cheese labelling. © 2023, Hrvatska Mljekarska Udruga. All rights reserved

Detection of Sparse Anomalies in High-Dimensional Network Telescope Signals

Network operators and system administrators are increasingly overwhelmed with incessant cyber-security threats ranging from malicious network reconnaissance to attacks such as distributed denial of service and data breaches. A large number of these attacks could be prevented if the network operators were better equipped with threat intelligence information that would allow them to block or throttle nefarious scanning activities. Network telescopes or "darknets" offer a unique window into observing Internet-wide scanners and other malicious entities, and they could offer early warning signals to operators that would be critical for infrastructure protection and/or attack mitigation. A network telescope consists of unused or "dark" IP spaces that serve no users, and solely passively observes any Internet traffic destined to the "telescope sensor" in an attempt to record ubiquitous network scanners, malware that forage for vulnerable devices, and other dubious activities. Hence, monitoring network telescopes for timely detection of coordinated and heavy scanning activities is an important, albeit challenging, task. The challenges mainly arise due to the non-stationarity and the dynamic nature of Internet traffic and, more importantly, the fact that one needs to monitor high-dimensional signals (e.g., all TCP/UDP ports) to search for "sparse" anomalies. We propose statistical methods to address both challenges in an efficient and "online" manner; our work is validated both with synthetic data as well as real-world data from a large network telescope

The design and synthesis of mechanism-based inhibitors of serine proteases

Serine proteases are involved in a number of physiological processes and have proved to be a valuable therapeutic target in the treatment of disease states resulting when the above processes move beyond homeostasis. The investigation of low molecular weight compounds as irreversible and reversible inhibitors of serine proteases has been fuelled by the possibility of rational drug design and their use as mechanistic probes of enzyme action. As introduced in Chapter one particular attention has been focused on mechanism-based inactivators as these elicit clinically desirable specific, efficient and irreversible inhibition. The synthesis and assay of funtionalised imide mechanism-based inhibitors of the serine protease α-chymotrypsin is the subject of this thesis. N-[(Sulfonyl)oxy]succinimides of type 1.41 (L=SO₂R') are known mechanism-based inhibitors of α-chymotrypsin operating via a Lossen rearrangement that unmasks an inactivating isocyanate species. Inhibitory activity has been found to be mediated by the nature of the R substituent and the R' substituent of the L group. Structure activity relationships were investigated by preparing a number of derivatives of type 1.41. The design of the derivatives prepared focused on modulating the R' substituent to interact with extended binding sites of α-chymotrypsin, a strategy that would enhance inhibitory activity. Chapter 2 describes the synthesis of 1.41 and 2.1. Retrosynthetic analysis identified a route involving N-hydroxyimides to be favoured. A synthesis of 1.41 and 2.1 via this key intermediate required reaction between hydroxylamine and succinic and glutaric acid derivatives respectively. These derivatives were prepared using literature methods employing Guareschi, Michael and malonate ester reactions. A systematic study of the synthesis of succinic acids found the optimum route to involve the Stobbe condensation however a short synthesis employing amide base alkylation of succinimide was undertaken and this methodology may prove to be the ideal general route. An aromatic series of derivatives, 1.41f-h was therefore synthesised using the methodology above as were "dimeric" inhibitors 1.41m and n capable of releasing two equivalents of inactivating species during inhibition. Succinimides with 3-C phenyl substituent rather than the benzyl substituent of the derivatives above, were prepared and a series of N-[(sulfonyl)oxy]glutarimides 2.1a, c-e where the extent and type of substitution were varied were prepared. N-[(Acyl)oxy]imides 1.41r-o and 2.1b (L=C(O)R') may also inhibit α-chymotrypsin and these too were investigated. Chapter 3 discusses the assay of inhibitory activity of compounds of type 1.41 and 2.1 against α-chymotrypsin. All the synthesised derivatives, excepting a series of N[(acyl)oxy]succinimides 1.41o-r, were found to be active to such a degree that all but one of the active compounds could not be assayed using sampling techniques. These potent inhibitors were then assayed using the progress curve method. Three compounds 1.41g and hand 2.1c were of such potency that the rate at which they inhibited achymotrypsin could not be measured even with the progress curve method. All three of these compounds possessed a benzyl substituent which was found to be a requiremnent for the exhibition of mechanism-based inhibition in the succinimide series. Compounds 1.41g and 1.41h owed their potency to being able to interact favourably with the Sn' subsites of α-chymotrypsin by containing aromatic substitution. Chapter 4 discusses the use of Evan's oxazolidinone chemistry in the preparation of chiral succinates from which an enantiopure inhibitor of type 1.41 was prepared. Preliminary inhibition studies showed that (R)-1.41f was less active than its racemate indicating more activity resided in the (S)-enantiomer. Chapter 5 discusses the design and synthesis of a potential novel imide mechanism-based inhibitor thought to act by unmasking a quinone imine methide in the active site of α-chymotrypsin. Although the compound released reactivity on hydrolysis it was not found to inhibit α-chymotrypsin significantly

Povezanost inzulinu sličnog faktora rasta tip 1 i intrauterinog rasta

Insulin-like growth factor 1 (IGF-1) is a regulator of intrauterine growth, and circulating concentrations are reduced in intrauterine growth-restricted fetuses. The aim of our study was to investigate the relationship between IGF-1 levels in newborns and intrauterine growth, expressed as birth weight (BW). The research was designed as a cross-sectional study. The study included 71 premature newborns, gestational age (GA) ≤33 weeks. Quantitative determination of IGF-1 was performed in the 33rd post-menstrual week (pmw) to make the measurements more comparable. We used an enzyme-bound immunosorbent test for quantitative determination of IGF-1. Our results showed the mean IGF-1 level in premature newborns in 33rd pmw to be 23.1±4.56 (range 15.44-39.75) μg/L. There was no difference in IGF-1 values between male (23.1±4.98 μg/L) and female (23.1±4.87 μg/L) newborns. Tere was no significant difference in the average IGF-1 levels between male and female newborns with BW 50th percentile for GA either (p>0.50). Only BW <33rd percentile newborns had a statistically significantly lower IGF-1 level compared to newborns with greater BW. Based on our results, it is concluded that serum IGF-1 level reflects intrauterine growth only in BW <33rd percentile newborns. This fact could be used for further therapeutic purposes.Inzulinu sličan faktor rasta (IGF-1) je jedan od čimbenika koji utječu na intrauterini rast. Serumske razine IGF-1 su smanjene u fetusima s intrauterinim zastojem rasta. Cilj našega istraživanja bio je ispitati odnos između razine IGF-1 u nedonoščadi i intrauterinog rasta izraženog kao porođajna težina (PT). Istraživanje je provedeno kao presječna studija. U studiju je bilo uključeno 71 nedonošče gestacijske dobi (GD) ≤33 tjedna. Kvantitativno određivanje IGF-1 provedeno je u 33. postmenstruacijskom tjednu (pmt) radi bolje usporedivosti rezultata. Za kvantitativno određivanje IGF-1 rabili smo enzimski imunosorbentni test. Naši rezultati pokazali su da je srednja razina IGF-1 u nedonoščadi u 33. pmt iznosila 23,1±4,56 (raspon 15,44-39,75) μg/L. Nije bilo razlike u vrijednostima IGF-1 između muške (23,1±4,98 μg/L) i ženske (23,1±4,87 μg/L) nedonoščadi. Također nije bilo značajne razlike u srednjim razinama IGF-1 između nedonoščadi s PT 50. percentila za GD (p>0,50). Nedonoščad s niskom PT (<33. percentila) imala su statistički značajno nižu razinu IGF-1. Na temelju naših rezultata može se zaključiti da serumska razina IGF-1 odražava intrauterini rast samo u nedonoščadi male PT (<33. percentila), što bi mogao biti koristan podatak za buduću uporabu IGF-1 u terapijske svrhe

Acquisition and Representation of Grammatical Categories: Grammatical Gender in a Connectionist Network

In traditional models of language production grammatical categories are represented as abstract features independent of semantics and phonology. An alternative view is proposed where syntactic categories emerge as a higher-order regularity from semantic and phonological properties of words. The proposal was tested using grammatical gender in Serbian, a south Slavic language with rich morphology. Semantic and phonological correlates of gender are described using a corpus of 1221 Serbian nouns. A PDP network was trained to produce the same words based on distributed semantic representation as input and distributed phonological representation as output, and with no explicit representation of grammatical gender. Upon successful learning of the training corpus, generalization was explored using test corpora designed to capture semantic and phonological properties of different genders. The findings suggest that grammatical gender, as other syntactic categories, may be viewed as emerging through coherent co-variation of semantic and phonological properties of words during learning