Metal complexes as potential ligands : the deprotonation of aminephenolate metal complexes

The cationic nickel, copper and zinc complexes of tris-(2-hydroxybenzyl)-aminoethylamine (H6TrenSal) have been deprotonated using potassium hydroxide. The nickel complex can be sequentially deprotonated to form a series of compounds namely, [(H6TrenSal)Ni]+, [(H6TrenSal)Ni] and "[(H6TrenSal)Ni]K". The latter is isolated as a mixture of species namely [{(H6TrenSal)Ni}K(EtOH)]2, [{(H6TrenSal)Ni}K(EtOH)2-μ-OH2]2 and [{(H6TrenSal)Ni}K(EtOH)2-μ-EtOH]2, which co-crystallise in a roughly 50:27.5:22.5 ratio. In contrast the deprotonation of [(H6TrenSal)M]+ (M = Cu, Zn) results in the formation of tetrameric complexes [({(H6TrenSal)Ni}K(OH2)2)4(μ4-OH2)]

Ultra-high throughput string matching for deep packet inspection

Deep Packet Inspection (DPI) involves searching a packet's header and payload against thousands of rules to detect possible attacks. The increase in Internet usage and growing number of attacks which must be searched for has meant hardware acceleration has become essential in the prevention of DPI becoming a bottleneck to a network if used on an edge or core router. In this paper we present a new multi-pattern matching algorithm which can search for the fixed strings contained within these rules at a guaranteed rate of one character per cycle independent of the number of strings or their length. Our algorithm is based on the Aho-Corasick string matching algorithm with our modifications resulting in a memory reduction of over 98% on the strings tested from the Snort ruleset. This allows the search structures needed for matching thousands of strings to be small enough to fit in the on-chip memory of an FPGA. Combined with a simple architecture for hardware, this leads to high throughput and low power consumption. Our hardware implementation uses multiple string matching engines working in parallel to search through packets. It can achieve a throughput of over 40 Gbps (OC-768) when implemented on a Stratix 3 FPGA and over 10 Gbps (OC-192) when implemented on the lower power Cyclone 3 FPGA

Multi-engine packet classification hardware accelerator

As line rates increase, the task of designing high performance architectures with reduced power consumption for the processing of router traffic remains important. In this paper, we present a multi-engine packet classification hardware accelerator, which gives increased performance and reduced power consumption. It follows the basic idea of decision-tree based packet classification algorithms, such as HiCuts and HyperCuts, in which the hyperspace represented by the ruleset is recursively divided into smaller subspaces according to some heuristics. Each classification engine consists of a Trie Traverser which is responsible for finding the leaf node corresponding to the incoming packet, and a Leaf Node Searcher that reports the matching rule in the leaf node. The packet classification engine utilizes the possibility of ultra-wide memory word provided by FPGA block RAM to store the decision tree data structure, in an attempt to reduce the number of memory accesses needed for the classification. Since the clock rate of an individual engine cannot catch up to that of the internal memory, multiple classification engines are used to increase the throughput. The implementations in two different FPGAs show that this architecture can reach a searching speed of 169 million packets per second (mpps) with synthesized ACL, FW and IPC rulesets. Further analysis reveals that compared to state of the art TCAM solutions, a power savings of up to 72% and an increase in throughput of up to 27% can be achieved

Energy Efficient Hardware Accelerators for Packet Classification and String Matching

This thesis focuses on the design of new algorithms and energy efficient high throughput hardware accelerators that implement packet classification and fixed string matching. These computationally heavy and memory intensive tasks are used by networking equipment to inspect all packets at wire speed. The constant growth in Internet usage has made them increasingly difficult to implement at core network line speeds. Packet classification is used to sort packets into different flows by comparing their headers to a list of rules. A flow is used to decide a packet’s priority and the manner in which it is processed. Fixed string matching is used to inspect a packet’s payload to check if it contains any strings associated with known viruses, attacks or other harmful activities. The contributions of this thesis towards the area of packet classification are hardware accelerators that allow packet classification to be implemented at core network line speeds when classifying packets using rulesets containing tens of thousands of rules. The hardware accelerators use modified versions of the HyperCuts packet classification algorithm. An adaptive clocking unit is also presented that dynamically adjusts the clock speed of a packet classification hardware accelerator so that its processing capacity matches the processing needs of the network traffic. This keeps dynamic power consumption to a minimum. Contributions made towards the area of fixed string matching include a new algorithm that builds a state machine that is used to search for strings with the aid of default transition pointers. The use of default transition pointers keep memory consumption low, allowing state machines capable of searching for thousands of strings to be small enough to fit in the on-chip memory of devices such as FPGAs. A hardware accelerator is also presented that uses these state machines to search through the payloads of packets for strings at core network line speeds

Metaphors of drama in some recent British fiction

Metaphors of drama and the concept of dramatic action offer a valuable way to approach the fiction of the post -Modern period in Britain. The subject of "role- playing" is an important one in recent social science, but one need not have recourse to any one or another theory of role - behaviour in order to comprehend the use of metaphors of drama in contemporary fiction. Novelists themselves have been investigating fundamental areas of human experience for a long time and their works reveal important truths not dependent on a received theory -- if indeed there is such a thing -- of roles in society. This study tries to avoid the pitfalls open to those who use a naive concept of Society as a rigid set of institutions and roles which are somehow doled out to passive and accepting new members. In this it echoes, without necessarily endorsing, the Modern indifference to Society as a value. The term Society is avoided not out of any anti -social motive, but in order to attempt to employ a less over -worked set of terms which allow us to comprehend more fully the way in which the modern novel works and what it achieves with its methods.Dramatic role -playing is considered in this study, therefore, not primarily as a matter of accepting a position in a rigid, defined and stable society, and part of the purpose of this thesis is to comment on the inadequacy of generalizations about the Novel which see it as somehow inherently Social as a genre. Similarly, a number of generalizations about the "anti- Social" nature of the Modern period and the supposedly more orthodox, Social nature of the post -Modern period in Britain are considered. It is found that while the goal of modern fiction is not to foster accommodation to Society, it does insist on the need to admit the reality of a world beyond the limits of the individual ego and imagination. In this sense, the modern novel is "social" because it posits the prime requisite for the creation of a possible human society: the recognition of the world of the other. Dramatic metaphor expresses the interplay of inner and outer worlds and dramatic action is seen to be the way out of Romantic solipsism.The full range of meaning of metaphors of drama is suggested in the novels of Joyce Cary; here the second trilogy about the politician Chester Nimmo is studied in detail. The novels of Muriel Spark are considered as-episodes in one emergent novel which looks at the paradoxical question of telling truths by means of fictions -- fictions which can be novels or can be "poses" of the individual in face -to -face situations. Christopher Isherwood uses dramatic metaphors throughout his work and his themes are best expressed in his later novel A Single Man which is unified by dramatic metaphor. A study of metaphors of drama in the novels of Graham Greene reveals inconsistencies between the dramatic action engaged in by the characters in the novels and that of the novelist who is also a poser whose novel is his persona, or way of appearing to the world. The endings of two of John Fowles' novels are studied as ritual dramas which are the f ocal points of the individual works. In the concluding chapter a number of other novelists are considered, including Kingsley Amis and Saul Bellow. Perhaps the most important figure in the last chapter is Iris Murdoch whose work is apparently a contradiction of many of the themes developed in the body of the thesis

N-heterocyclic germylenes: structural characterisation of some heavy analogues of the ubiquitous N-heterocyclic carbenes

The X-ray crystal structures of three N-heterocyclic germylenes (NHGes) have been elucidated including the previously unknown 1,3-bis(2,6-dimethylphenyl)diazagermol-2-ylidene (1). In addition, the X-ray crystal structures of the previously synthesised 1,3-bis(2,4,6-trimethylphenyl)diazagermol-2-ylidene (2) and 1,3-bis(2,6-diisopropylphenyl)diazagermol-2-ylidene (3) are also reported. The discrete molecular structures of compounds 1 to 3 are comparable, with Ge-N bond lengths in the range 1.835-1.875 Å, while the N-Ge-N bond angles range between 83.6 and 85.2°. Compound 2 was compared to the analogous N-heterocyclic carbene species, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes). The major geometrical difference observed, as expected, was the bond angle around the divalent group 14 atom. The N-Ge-N bond angle was 83.6° for compound 2 versus the N-C-N bond angle of 101.4° for IMes. The Sn equivalent of (1), 1,3-bis(2,6-dimethylphenyl)diazastannol-2-ylidene (4), has also been synthesised and its crystal structure is reported here. In order to test their suitability as ligands, compounds 1 to 3 were reacted with a wide range of transition metal complexes. No NHGes containing metal complexes were observed. In all cases the NHGe either degraded or gave no reaction

Disturbance and its effects on archaeological significance and integrity

Significance and integrity are key concepts for archaeology, and how they are judged is determined by an archaeologist’s perceptions of disturbance. This thesis explicitly considers these concepts and how they relate to evolutionary theory and National Register eligibility. A site with known disturbance was chosen to determine whether it could be judged significant assuming that there was no disturbance. Controlled surface collection, magnetometer survey, excavation and landowner interview data were used to determine whether what made the site significant had been lost due to disturbance. The results indicate that the co-mingling of occupations in the plow zone normally would have prevented the site from being determined eligible. However, because of the clusters of Gulf Formational-period diagnostics and intact Early Archaic midden, the site was determined significant. If future work were to be performed, occupation-based work focusing on the artifact clusters and the Archaic midden is recommended

Site Variation in Summer Foods of Arctic Fox, Prince of Wales Island, Northwest Territories

Analysis of 840 arctic fox (Alopex lagopus) feces (scats) from Prince of Wales Island, indicate that collared lemming (Dicrostonyx groenlandicus) are the most frequent food item. Caribou (Rangifer), arctic hare (Lepus arcticus) and ermine (Mustela erminea) were less important. Bird remains were not prevalent in the arctic fox scats. A marked difference was found between prey items at a den site and those recovered in scats from general searches. Caribou remains were more prevalent in scats from a den site because adult foxes were scavenging nearby wolf kills