This study researches the nonlinear optical properties of the blue phase liquid crystals using the Z-scan technique. The purpose is to investigate the non-linear effect of the blue phase liquid crystals induced by the thermal and the liquid crystal reorientation effect. The Z-scan technique is common method to measure the non-linear index n2 and the non-linear absorption coefficient of materials. The measurement of the optical Kerr constant using Z-scan is based on the principle of spatial beam distortion due to the self-focusing or self-defocusing. For typical nematic liquid crystals, the nonlinear effect in the nematic phase is large than that in the isotropic phase. However, due to the anisotropic properties of the liquid crystal, the light-induced nonlinear effect in the nematic phase is polarization dependency. Unlike nematic phase, the blue phase is optical isotropic duo to its symmetric structure, and therefore blue phase are polarization independent and provide a larger non-linear effect. The experiments to measure the nonlinear refractive index n2 are as follows: firstly, a linearly polarized Ar+ laser light (£f=532nm) is focused in the z direction onto the sample via lens, and the detector was set behind the sample. Sequentially, the light intensity is recorded while the sample is scanned near the beam waist of the green laser. Finally, the non-linear index n2 of the material is derived from mathematical calculation. The study investigated two kinds of material, pure blue phase liquid crystal and dye-doped blue phase liquid crystal, and measured their non-linear index n2 in the blue phase and isotropic phase, respectively. The experimental results show that the non-linear index n2 of dye-doped blue phase liquid crystal is 100~1000 times as large as this of the pure blue phase liquid crystal at the blue phase. Besides, compared with isotropic phase in the blue phase liquid crystal, the blue phase actually possesses larger non-linear index n2. This experiment confirms that the nonlinear effect can be induced using linearly polarized Ar+ laser, and the nonlinear refractive index n2 can be measured using Z-scan technique.

The purpose of this study was to integrate the principles of marine geotechnical engineering, underwater acoustic and optical observation techniques into studying the distribution of seafloor sediments and engineering stability of artificial reefs off Yong-an Harbor, Kaohsiung County, south-western coast of Taiwan. The artificial reefs were deployed to the testing site in November 9th, 1996. The goal of this study was intended to describe the engineering status of this reef site and to investigate whether these reefs were moved and buried or not; as well as, to predict whether additional reefs should be deployed to this site in the future. Long-term monitoring of underwater targets was conducted by using of side-scan sonar system, echo sounder, sub-bottom profiler, and underwater video camera. The utility of side-scan sonar system was to depict the topography and terrain features of the seabed. The other equipments were used to complement and cross correlate the results of side-scan sonar observations. In this study, wave forces against reef were estimated by Morison¡¦s equation(ex. Huang, 1995), scouring depth was calculated by Silvester¡¦s experience equation (Silvester, 1974), and the settlement of reefs by theoretical consolidation equation(ex. Das, 1990). The topography of Yung-an reef site is generally gentle and monotonous. The major texture of surficial sediments in this site was sandy silt, and some gravel was distributed at the southern part of the site. In terms of the stability on the artificial reefs project, Typhoon was the main factor which causes the reef to slide or roll. Verified by theoretical analysis and monitoring, the study area of the original stacked reefs has tumbled during the research period, while the remaining non-stacked reef shows insignificant displacement and quantity of the settlement found no cases being buried. To sum up, Yong-an artificial reef district in Kaohsiung county, respectively as A, B, C; the stacked reef under normal condition has found no significant reef being buried and moving traces and artificial reefs can fully elaborate by the gathers of the fish. According to the viewpoint of this project , "Direct contact with the reef and the body of the sea-bed " both the forces of the waves and ocean currents when a typhoon strikes is not easy for the reefs to glide. The "stacked reef" which causes the reef to slide or roll when typhoon occurs was caused by both the forces of the waves and ocean currents. "Direct contact with the reef and the body of the sea-bed " in the case of wave period of 10 sec, analysis shows that the wave height must be greater than 5.8 m in order to make the reef slide. "Stacked reef" in the case of wave period of 10 sec, analysis shows that the wave height must be greater than 4.5 m in order to make the reef roll.

In this thesis, the nonlinear properties of dye-doped liquid crystal films measured via Z-scan technique are presented, and we¡¦ve also compared the features of nonlinear effect between nematic and cholesteric liquid crystals, because the purpose was to obtain a strong nonlinear effect which is polarization independent. The nonlinear refraction of the samples would induce self-focusing/self-defocusing effect, therefore the Z-scan technique was utilized for the measurements in this study. The degrees of self-focusing/self-defocusing effect can be used to calculate the optical Kerr constants n2 related to the variation of refractive indices. Moreover, this technique is uncomplicated and powerful for nonlinear effect observations, because it only requires a single laser beam and a simple setup to measure both nonlinear refractive indices and nonlinear absorption coefficients. In the first section of the study, we had investigated the nonlinear effect of azo-dye-doped liquid crystal (ADDLC) films by Z-scan technique. Owing to the birefringence provided by homogeneous-alignment liquid crystal films and the absorption difference between the long axis and the short axis of the azo dye, the self-defocusing effect in nematic phase was larger than that in isotropic state as the polarization of incident light was parallel to the long axis of aligned liquid crystals. While we set the incident polarization perpendicular to the long axis of liquid crystals, a self-focusing effect was observed and the in nematic phase was found smaller than that in isotropic state. As a result, it can be analyzed that the nonlinear effect of homogeneous aligned ADDLC films is intensely polarization-dependent. In the second section, in order to acquire a polarization-independent nonlinear effect, we fabricated the azo-dye-doped cholesteric liquid crystal (ADDCLC) films which were arranged in planar texture with the reflection bands managed to avoid the III wavelength of incident light. We had studied the nonlinear effects in different concentrations of the azo dye and also measured the influence of incident polarizations. We discover that when the concentration of dyes was raised, the n2 increased as well; the nonlinear indices were almost the same in various polarized light. The incident light suffered an average refractive index in an ADDCLC film, and azo dye arranged in helices resulted in identical absorption to different polarized light. In summary, employing ADDCLCs with planar texture in nonlinear optical applications, we could achieve not only strong nonlinear effects but also high polarization independence in liquid crystals.

The primary goal of the Thoroughbred industry is to breed and train superior equine athletes capable of excelling on the racetrack. To date, research into the genetic underpinnings of athletic ability has been limited in the horse. Advances in equine genomics and the genetics of athletic performance in humans have opened up the possibility of investigating this important trait in the Thoroughbred. Initially, 46 candidate genes associated with human athletic performance were mapped in the equine genome by radiation hybrid (RH) and fluorescent in situ hybridization (FISH) mapping. RH data and later the draft equine genomic sequence allowed us to identify microsatellites adjacent to these and other candidate genes (95 in total). Additional microsatellites were added to increase genome coverage, producing a final panel of 186 markers. All the potential markers were initially screened on a pool of DNA for 16 Thoroughbreds to ensure they were polymorphic. The panel was genotyped on 162 Thoroughbreds in total; Centimorgans (cM) between microsatellites were determined with CRI-MAP. The animal?s athletic ability was estimated using career winnings loge transformed to create a linear trait; unraced animals were treated as missing data. Linkage analysis was carried out using the MERLIN program, and association analysis was carried out using the QTDT program. Appropriate thresholds for statistical significance were determined by carrying out 1000 simulated genome scans based on the structure of the original data. LOD scores above 1.54 met the criteria of statistical significance (with a 5% chance of type I error). In the actual genome scan, the marker L12.2 had the highest observed LOD score of 1.16 and p-value of 0.01 and consequently was not significant; the association analysis also did not detect significant association with performance on the track. Given the complexity of the phenotype under investigation and the modest sample size, the lack of linkage/association was not unexpected. Nevertheless, this study has contributed to the RH and FISH maps of the equine genome. Additionally, the development of the genome scanning panel for this study has provided useful information on the most informative microsatellites for linkage or association studies in the Thoroughbred.

Consider a piece of information printed on paper and scanned in the form of an image. The printer, scanner, and the paper naturally form a communication channel, where the printer is equivalent to the sender, scanner is equivalent to the receiver, and the paper is the medium of communication. The channel created in this way is quite complicated and it maps 2D input patterns to 2D output patterns. Inter-symbol interference is introduced in the channel as a result of printing and scanning. During printing, ink from the neighboring pixels can spread out. The scanning process can introduce interference in the data obtained because of the finite size of each pixel and the fact that the scanner doesn't have infinite resolution. Other degradations in the process can be modeled as noise in the system. The scanner may also introduce some spherical aberration due to the lensing effect. Finally, when the image is scanned, it might not be aligned exactly below the scanner, which may lead to rotation and translation of the image. In this work, we present a coding scheme for the channel, and possible solutions for a few of the distortions stated above. Our solution consists of the structure, encoding and decoding scheme for the code, a scheme to undo the rotational distortion, and an equalization method. The motivation behind this is the question: What is the information capacity of paper. The purpose is to find out how much data can be printed out and retrieved successfully. Of course, this question has potential practical impact on the design of 2D bar codes, which is why encodability is a desired feature. There are also a number of other useful applications however. We could successfully decode 41.435 kB of data printed on a paper of size 6.7 X 6.7 inches using a Xerox Phasor 550 printer and a Canon CanoScan LiDE200 scanner. As described in the last chapter, the capacity of the paper using this channel is clearly greater than 0.9230 kB per square inch. The main contribution of the thesis lies in constructing the entire system and testing its performance. Since the focus is on encodable and practically implementable schemes, the proposed encoding method is compared with another well known and easily encodable code, namely the repeat accumulate code.

With the advanced technology, our life has improved, however, it also brings the new model of crime events. Because the intrusion technique and intrusion tools are developed day by day, many computer crimes such as overstep system authority, intrusion events, computer crime, and network attack incidents are happening everywhere and everyday. In fact, those kinds of animus attack behaviors are troublesome problems. Staffs of network management may have to read security advisory, which is sent out by security organization. For example, they have to subscribe advisories for Computer Emergency Response Team or security mail list to continuously accumulate their security information. In addition, in the security protect system, they may need to spend huge fund to purchase firewall system, intrusion detection system, antivirus system and other related security protect systems. These attack behaviors have been evolved from one computer attacked to heavy attack by new intrusion model such as worm to proceed large scale spread attacking recently. Furthermore, each attack use different communication protocol and port, which is aimed at the system vulnerability, it is not easy to detect these attacks. If we can observe the variation of network traffic to detect the unusual hosts, for controlling the usage of network or occurring extraordinary phenomenon, it could help network managers to discover and solve network attack problems in time. Lately, many intrusion events have been happened increasingly, and the denial-of-service has become the most serious network event of the Computer Crime and Security Survey of FBI/CSI in 2003. Therefore, in various attacking types, we choose vulnerability scan and denial-of-service as our research direction. This research extend to develop IPAudit[16], a network traffic monitor system, which is to detect hosts flows traffic of the local area network. We establish network attack rules by using data miningclassification (C4.5) to analyze attack data, and we estimate the correctness percentage of classification. This study also uses different attack applications for the same attack type to process the cross experiment. The result has shown that the technology of data mining classification (C4.5) can help us to forecast efficiently the same attack type events.

In recent years, ocean has become a place to dispose of industrial and civil waste waters. Hence, there are more and more projects to establish offshore outflow pipes. These underwater pipes should be kept monitored in order to maintain their functions specifically. The purpose of this research was to explore the two outflow pipes in Kaohsiung offshore area, i.e., Chung-chou outflow pipe and Tso-ying outflow pipe, by using an integrated surveying system which includes a side-scan sonar and a sub-bottom profiler. The ultimate objective was to investigate the feasibility of this system in searching and positioning of buried underwater pipelines. Based on this investigation, the offshore section of Chung-chou outflow pipe is about 2.8km in length and extends offshore to the direction of 38o from the west to the south. The water depth at the end of this pipe is about 21m. Among the 2.24km section initiated at the offshore end of the pipe, the buried depths are between 2.2m and 3.2m. There are two disposed gravel zones around the offshore end of the pipe. The first zone is about 130m in length and 10m wide. The second zone is 220m in length and 20m wide. Moreover, based on the side scan sonar images, there are 71 protective concrete blocks located around Chung-chou outflow pipe. The offshore section of Tsao-ying outflow pipe is about 4.76 km in length and extends to the direction of 20o from the west to the south. The water depth at the end of this pipe is about 17m. Among the 3.7km section initiated at the offshore end of the pipe, the buried depths are about 1.0 to 2.5m. A disposed gravel zone with dimensions of 330m in length and 10m wide is located at the end of this pipe. In addition, there are 43 protective blocks located around this outflow pipe. This investigation, incorporated the results conducted on the other three underwater outflow pipes(i.e., Chishui creek outflow pipe, Chinese Petroleum Corporation underwater petroleum pipe off Kaohsiung Harbor and Liuchiuyu water transport pipe), concluded that as far as the buried underwater pipes that are thicker than 1m in diameter are concerned, the integrated system of side scan sonar and sub-bottom profiler provides an useful and trustful tool to get the locations and the buried depth of outflow pipes, as well as the distribution of the protective concrete blocks around these pipes. As to the pipes that are less than 20cm in diameter, the pipes can¡¦t be detected by this equipment. For the pipes that are between 20cm and 1m in diameter, due to limited information collected up to this moment, extensive investigation need to be conducted until a clear understanding can be deduced.

Underwater static targets are objects under the water that can¡¦t move autonomously. Apparatus feasible for detecting underwater static targets includes: optics, acoustics and geophysical instruments. The purpose of this research is discussing the efficiency of applying side-scan sonar, magnetometer, sub-bottom profiler and echo sounder simultaneously to search, detect, identify and locate underwater static targets. Procedures of this research include: 1. Discussing the capabilities of instruments and identification principles on target. 2. Using a real case to groundtruth target identification principles. 3. Assessing the superiority of the methodology. According to the characteristics of these apparatus, the water depth, collected by echo sounder, is capable of expressing the relief of the seabed. Seabed sonographs, recorded by side-scan sonar, show that it is feasible to detect, identify and locate targets on the seabed. Sub-bottom profiler provides the sub-surface sedimentary information which can be used to detect buried targets. Magnetometer can detect environmental magnetic intensities, which can locate and determine the size of ferrous targets. Analysis of the data collected at Hai-Köu Wan, Ping-Dong County yields following conclusions: 1. The water depth data, recorded per 15 meters by the echo sounder, is capable of detecting large targets and concentrated artificial reefs only. 2. Sonographs obtained by side-scan sonar show target¡¦s characteristics and location on seabed. It can be utilized to identifying targets and mapping targets distributions. 3. Sub-bottom profile graphs show the composition and thickness of sub-surface sediments. 4. Magnetic anomalies show that there are evident variations around the battle-ship reef or concentrated electric-pole reefs on the research area. It represents that the magnetometer is capable in detecting underwater ferrous targets. 5. Targets detecting rate and identifying accuracy can be increased by the mutual comparison of various information. By applying the technique established in this research and the survey results at Hai-Köu Wan, targets at the survey site can be identified and located precisely. There are about 1100 units of 2-m concrete reefs, 670 units of electric-pole reefs and a battle-ship reef at Hai-Köu Wan. It can be concluded that, applying echo-sounder, side-scan sonar system, sub-bottom profiler and magnetometer simultaneously can search, detect, identify and locate underwater static targets more effective than applying a single instrument such as side-scan sonar system.

Simpson Bay is a turbid, outwash fjord located in northeastern Prince William Sound, Alaska. A high ratio of watershead:basin surface area combined with high precipitation and an easily erodable catchment create high sediment inputs. Fresh water from heavy precipitation and meltwater from high alpine glaciers enter Simpson Bay through bay head rivers and small shoreline creeks that drain the catchment. Side scan sonar, seismic profiling, and high resolution bathymetry were used to investigate the record of modern sedimentary processes. Four bottom types and two seismic faces were described to delineate the distribution of sediment types and sedimentary processes in Simpson Bay. Sonar images showed areas of high backscatter (coarse grain sediment, bedrock outcrops and shorelines) in shallow areas and areas of low backscatter (estuarine mud) in deeper areas. Seismic profiles showed that high backscatter areas reflected emergent glacial surfaces while low backscatter areas indicated modern estuarine mud deposition. The data show terminal morainal bank systems and grounding line deposits at the mouth of the bay and rocky promontories, relict medial moraines, that extend as terrestrial features through the subtidal and into deeper waters. Tidal currents and mass wasting are the major influences on sediment distribution. Hydrographic data showed high spatial variability in surface and bottom currents throughout the bay. Bottom currents are tide dominated, and are generally weak (5-20 cm s-1) in the open water portions of the bay while faster currents are found associated with shorelines, outcrops, and restrictive sills. Tidal currents alone are not enough to cause the lack of estuarine mud deposition in shallow areas. Bathymetric data showed steep slopes throughout the bay suggesting sediment gravity flows. Central Alaska is a seismically active area, and earthquakes are most likely the triggering mechanism of the gravity flows.

Knowledge of surface sediment distribution in Galveston Bay is important because it allows us to better understand how the bay works and how human activities impact the bay and its ecosystems. In this project, six areas of bay bottom were surveyed using acoustic techniques to make maps of bay bottom types and to investigate the types and extent of anthropogenic impacts. A total of 31 km2 was surveyed in six areas, one in Bolivar Roads (6.1 km2), one near Redfish Bar (3.1 km2), two in East Bay (12 km2), one southeast of the Clear Lake entrance (5.3 km2), and one in Trinity Bay (4.3 km2). Sidescan sonars (100 kHz and 600 kHz) were used to image the bay bottom, and a chirp sonar (2-12 kHz) was used to image subsurface sediment layers and bottom topography. In the side-scan records, objects as small as a few meters in extent were visible, whereas the chirp sonar records show a vertical resolution of a few tens of centimeters. The sidescan images display strong backscatter in some areas due to coarse sediments in addition to weak backscatter in areas of fine sediment. The bay bottom was classified using three levels of sonar backscatter ranging from high to low. Areas of differing sonar backscatter intensity were sampled with cores and grab-samples. High backscatter corresponded to coarse shell debris and oyster reefs, medium backscatter corresponded to a sand-silt-shell mixture, and low backscatter corresponded to silty loam. Chirp sonar records were classified as one of nine different bottom reflection types based on changes in amplitude and stratigraphy. Parallel, layered sediments are seen filling the bay valley and resting atop a sharp contact at which the acoustic signal fades out. Along the flanks of the valley fill the acoustic response revealed an absent or weakly laminated stratigraphy, whereas areas of high oyster productivity produced mounds, strong surface returns, and strong, shallow subsurface reflectors surrounding current oyster reefs. Anthropogenic features imaged with the sonar included sediment disruptions, such as the ship channels, dredge holes, gouges, and trawl marks, as well as debris, such as submerged boats, pipes, and unidentified objects.