This report deals with the issue of tense and aspect system in Korean both semantically and syntactically. Previous accounts for tense and aspect in Korean have been based on the assumption that the suffix has a fixed meaning, either temporally or aspectually, and either perfect(ive) or imperfective, and so on. In this report, I argue that the interpretation of the temporal suffix in Korean must be more flexible. The interpretation of the suffix is dependent on the occurrence conditions such as the characteristics of the verbs (or the predicates) and the temporal adverbials. For this claim, I argue how to understand tense and viewpoint aspect in Korean based on ‘twocomponent theory of aspect’ (Smith 1997) along the line of ‘boundedness’ of the grammaticalized aspect (Depraetere 1995) and ‘Event realization’ by Bohnemeyer and Swift (2004): –ess is either past tense or perfective aspect suffix and –nun is a present tense suffix with imperfective aspect meaning, because –nun only occurs with [+dynamic] predicates. Further, I argue how we can reflect the semantic tense and aspect onto the syntactic representation properly. Following Demirdache & Uribe-Etxebarria (1997, 2000), I show how tense and aspect in Korean can be mapped onto the syntactic representation. To treat the temporal adverbials, I follow Thompson (2005) that temporal adverbials are linked to [spec, AspP] position when they play a role as Reference Time (RT). Finally, I argue how the relations of the temporal arguments are syntactically realized in Korean. And –ess is interpreted as perfective aspect when the RT and ST (Speech Time) overlap. / text

Zugl.: Coimbra, Univ., Diss., 2007

Thesis (Doctoral)--Rheinische Friedrich-Wilhelms-Universität zu Bonn, 1930.

Genomic sequence databases, like GenBank, EMBL, are widely used by molecular biologists for homology searching. Because of the increase of the size of genomic sequence databases, the importance of indexing the sequences for fast queries grows. The DNA sequences are composed of 4 base pairs, and these genomic sequences can be regarded as the text strings. Similar to conventional databases, there are some approaches use indexes to provide efficient access to the data. The inverted-list indexing approach uses hashing to store the database sequences. However, the perfect hashing function is difficult to construct, and the collision in a hash table may occur frequently. Different from the inverted-list approach, there are other data structures, such as the suffix tree, the suffix array, and the suffix binary search tree, to index the genomic sequences. One characteristic of those suffix-tree-like data structures is that they store all suffixes of the sequences. They do not break the sequences into words. The advantage of the suffix tree is simple. However, the storage space of the suffix tree is too large. The suffix array and the suffix binary search tree reduce more storage space than the suffix tree. But since they use the binary searching technique to find the query sequence, they waste too much time to do the search. Another data structure, the word suffix tree, uses the concept of words and stores partial suffixes to index the DNA sequence. Although the word suffix tree reduces the storage space, it will lose information in the search process. In this thesis, we propose a new index structure, ACGT-Words tree, for efficiently support query processing in genomic databases. We define the concept of words which is different from the word definition given in the word suffix tree, and separate the DNA sequences stored in the database and in the query sequence into distinct words. Our approach does not store all of the suffixes in the database sequences. Therefore, we need less space than the suffix tree approach. We also propose an efficient search algorithm to do the sequence match based on the ACGT-Words tree index structure; therefore, we can take less time to finish the search than the suffix array approach. Our approach also avoids the missing cases in the word suffix tree. Then, based on the ACGT-Words tree, we propose one improved operation for data insertion and two improved operations for the searching process. In the improved operation for insertion, we sort the ACGT-Words generated and then preprocess them before constructing the tree structure. In the two improved operations, we can provide better performance when the query sequence satisfies some conditions. The simulation results show that the ACGT-Words tree outperforms the suffix tree and the suffix array in terms of storage and processing time, respectively. Moreover, we show that the improved operations in the ACGT-Words tree also require shorter time to construct or search than the original processes or the suffix array.

Zugl.: Bonn, Universiẗat, Diss., 2004.

Over the last decade, biological sequence repositories have been growing at an exponential rate. Sophisticated indexing techniques are required to facilitate efficient searching through these humongous genetic repositories. A particularly attractive index structure for such sequence processing is the classical suffix-tree, a vertically compressed trie structure built over the set of all suffixes of a sequence. Its attractiveness stems from its linearity properties -- suffix-tree construction times are linear in the size of the indexed sequences, while search times are linear in the size of the query strings. In practice, however, the promise of suffix-trees is not realized for extremely long sequences, such as the human genome, that run into the billions of characters. This is because suffix-trees, which are typically an order of magnitude larger than the indexed sequence, necessarily have to be disk-resident for such elongated sequences, and their traditional construction and traversal algorithms result in random disk accesses. We investigate, in this thesis, post-construction techniques for disk-based suffix-tree storage optimization, with the objective of maximizing disk-reference locality during query processing. We begin by focusing on the layout reorganization in which the node-to-block assignments and sequence of blocks are reworked. Our proposed algorithm is based on combining the breadth-first layout approach advocated in the recent literature with probabilistic techniques for minimizing the physical distance between successive block accesses, based on an analysis of node traversal patterns. In our next step, we consider techniques for reducing the space overheads incurred by suffix-trees. In particular, we propose an embedding strategy whereby leaf nodes can be completely represented within their parent internal nodes, without requiring any space extension of the parent node's structure. To quantitatively evaluate the benefits of our reorganized and restructured layouts, we have conducted extensive experiments on complete human genome sequences, with complex and computationally expensive user queries that involve finding the maximal common substring matches of the query strings. We show, for the first time, that the layout reorganization approach can be scaled to entire genomes, including the human genome. In the layout reorganization, with careful choice of node-to-block assignment condition and optimized sequence of blocks, search-time improvements ranging from 25% to 75% can be achieved with respect to the construction layouts on such genomes. While the layout reorganization does take considerable time, it is a one-time process whereas searches will be repeatedly invoked on this index. The internalization of leaf nodes results in a 25% reduction in the suffix-tree space occupancy. More importantly, when applied to the construction layout, it provides search-time improvements ranging from 25% to 85%, and in conjunction with the reorganized layout, searches are speeded up by 50% to 90%. Overall, our study and experimental results indicate that through careful choice of node implementations and layouts, the disk access locality of suffix-trees can be improved to the extent that upto an order-of-magnitude improvements in search-times may result relative to the classical implementations.

The thin-client/server computing model mandates applications running solely on a server and client devices connecting to the server through the Internet for carrying out works. Traditional thin-client/server computing model comprises only a single server and works only within LAN environment, which severely restrict its applicability. To meet the demand of reasonable response time over WAN, a modified thin-client/server computing model, MAS TC/S, was proposed. In MAS TC/S, multiple application servers spreading over WAN are installed, and each client device can freely connect to any application server that is close to it. However, reducing delay associated with fetching absent files, which are stored in other servers, is a challenging issue in MAS TC/S. We propose to employ data prefetching mechanisms to speed up file fetching. We use the suffix tree-like structure to store users¡¦ previous file access records and define two temporal relationships between two records: followed by or concurrent with, to decide the set of files that should be prefetched together. Each file access subsequence is associated with a set of predicted file sets, each carrying a different weight. Given a current file access session, we will first find a matching file access subsequence and then choose the predicted set that has the highest weight. Based on the chosen predicted set, suitable files are prefeteched to the connected server. We compare our method with All-Kth-Order Markov model and find our method gets higher hit ratio under various operating regions.

The locative suffix -ni: In this article we discuss two hypotheses about the origin of the locative suffix -ni. The better known hypothesis (Raum 1909; Meinhof 1941/42) assumes that the suffix -(i)ni developed out of a class 18 demonstrative, though the details of the assumed phonological changes have never been made clear. The competing hypothesis by Sacleux (1939) suggests that locative nouns with -ni started out as compounds with the noun ini `liver´. We think that this second hypothesis is phonologically more plausible and that it also accounts for the specific link with the meaning of class 18 `inside´. Comparison of the spread of the locative suffix -(i)ni and of the word ini `liver´, together with other historical considerations, point to Kiswahili (or Sabaki) as the most likely origin of this locative suffix.

The locative suffix -ni: In this article we discuss two hypotheses about the origin of the locative suffix -ni. The better known hypothesis (Raum 1909; Meinhof 1941/42) assumes that the suffix -(i)ni developed out of a class 18 demonstrative, though the details of the assumed phonological changes have never been made clear. The competing hypothesis by Sacleux (1939) suggests that locative nouns with -ni started out as compounds with the noun ini `liver´. We think that this second hypothesis is phonologically more plausible and that it also accounts for the specific link with the meaning of class 18 `inside´. Comparison of the spread of the locative suffix -(i)ni and of the word ini `liver´, together with other historical considerations, point to Kiswahili (or Sabaki) as the most likely origin of this locative suffix.

No description available.