Frequency Doubling Nanocrystals for Cancer Theranostics

A novel bio-photonics approach based on the nonlinear optical process of second harmonic generation by non-centrosymmetric nanoparticles is presented and demonstrated on malignant human cell lines. The proposed method allows to directly interact with DNA in absence of photosensitizing molecules, to enable independent imaging and therapeutic modalities switching between the two modes of operation by simply tuning the excitation laser wavelength, and to avoid any risk of spontaneous activation by any natural or artificial light source.Comment: 16 pages, 7 figure

Similarity Tests for Metamorphic Virus Detection

A metamorphic computer virus generates copies of itself using code morphing techniques. A new virus has the same functionality as the parent but it has a different internal structure. The goal of the metamorphic virus writer is to produce viral copies that have no common signature. If the viral copies are sufficiently different, they can evade signature detection, which is the most widely-used anti-virus technique.In previous research, hidden Markov models (HMMs) have been used to detect some metamorphic viruses. However, recent research has shown that it is possible for carefully designed metamorphic viruses to evade HMM-based detection.In this project, we analyze similarity-based techniques for detecting metamorphic viruses. We first consider a similarity index technique that was previously studied. We then consider new similarity techniques based on edit distance and pairwise sequence alignment. We test these similarity measures on the challenging problem of metamorphic virus detection. We compare our detection results with those obtained using an HMM-based detection method

Optical properties of Southern Hemisphere aerosols: Report of the joint CSIRO/NASA study

This study was made in support of the LAWS and GLOBE programs, which aim to design a suitable Doppler lidar system for measuring global winds from a satellite. Observations were taken from 5 deg S to 45 deg S along and off the E and SE Australian coast, thus obtaining representative samples over a large latitude range. Observations were made between 0 and 6 km altitude of aerosol physical and chemical properties in situ from the CSIRO F-27 aircraft; of lidar backscatter coefficients at 10.6 micron wavelength from the F-27 aircraft; of lidar backscatter profiles at 0.694 microns at Sale, SE Australia; and of lidar backscatter profiles at 0.532 microns at Cowley Beach, NE Australia. Both calculations and observations in the free troposphere gave a backscatter coefficient of 1-2 x 10 to the -11/m/sr at 10.6 microns, although the accuracies of the instruments were marginal at this level. Equivalent figures were 2-8 x 10 to the -9/m/sr (aerosol) and 9 x 10 to the -9 to 2 x 10 to the -8/m/sr (lidar) at 0.694 microns wavelength at Sale; and 3.7 x 10 to the -9/m/sr (aerosol) and 10 to the -8 to 10 to the -7/m/sr (lidar) at 0.532 microns wavelength at Cowley Beach. The measured backscatter coefficients at 0.694 and 0.532 microns were consistently higher than the values calculated from aerosol size distributions by factors of typically 2 to 10

A preliminary study of air-pollution measurement by active remote-sensing techniques

Air pollutants are identified, and the needs for their measurement from satellites and aircraft are discussed. An assessment is made of the properties of these pollutants and of the normal atmosphere, including interactions with light of various wavelengths and the resulting effects on transmission and scattering of optical signals. The possible methods for active remote measurement are described; the relative performance capabilities of double-ended and single-ended systems are compared qualitatively; and the capabilities of the several single-ended or backscattering techniques are compared quantitatively. The differential-absorption lidar (DIAL) technique is shown to be superior to the other backscattering techniques. The lidar system parameters and their relationships to the environmental factors and the properties of pollutants are examined in detail. A computer program that models both the atmosphere (including pollutants) and the lidar system is described. The performance capabilities of present and future lidar components are assessed, and projections are made of prospective measurement capabilities for future lidar systems. Following a discussion of some important operational factors that affect both the design and measurement capabilities of airborne and satellite-based lidar systems, the extensive analytical results obtained through more than 1000 individual cases analyzed with the aid of the computer program are summarized and discussed. The conclusions are presented. Recommendations are also made for additional studies to investigate cases that could not be explored adequately during this study

DYNAMIC ROUTING WITH CROSS-LAYER ADAPTATIONS FOR MULTI-HOP WIRELESS NETWORKS

In recent years there has been a proliferation of research on a number of wireless multi-hop networks that include mobile ad-hoc networks, wireless mesh networks, and wireless sensor networks (WSNs). Routing protocols in such networks are of- ten required to meet design objectives that include a combination of factors such as throughput, delay, energy consumption, network lifetime etc. In addition, many mod- ern wireless networks are equipped with multi-channel radios, where channel selection plays an important role in achieving the same design objectives. Consequently, ad- dressing the routing problem together with cross-layer adaptations such as channel selection is an important issue in such networks. In this work, we study the joint routing and channel selection problem that spans two domains of wireless networks. The first is a cost-effective and scalable wireless-optical access networks which is a combination of high-capacity optical access and unethered wireless access. The joint routing and channel selection problem in this case is addressed under an anycasting paradigm. In addition, we address two other problems in the context of wireless- optical access networks. The first is on optimal gateway placement and network planning for serving a given set of users. And the second is the development of an analytical model to evaluate the performance of the IEEE 802.11 DCF in radio-over- fiber wireless LANs. The second domain involves resource constrained WSNs where we focus on route and channel selection for network lifetime maximization. Here, the problem is further exacerbated by distributed power control, that introduces addi- tional design considerations. Both problems involve cross-layer adaptations that must be solved together with routing. Finally, we present an analytical model for lifetime calculation in multi-channel, asynchronous WSNs under optimal power control

쌍별 색 개선과 효율적인 백트래킹을 이용한 빠른 그래프 동형 알고리즘

학위논문(박사) -- 서울대학교대학원 : 공과대학 컴퓨터공학부, 2021.8. 구건모.Graph isomorphism is a core problem in graph analysis of various domains including social networks, bioinformatics, chemistry, and so on. As real-world graphs are getting bigger and bigger, applications demand practically fast algorithms that can run on large-scale graphs. Existing approaches, however, show limited performances on large-scale real-world graphs either in time or space. Also, graph isomorphism query processing is often required in many applications, which is a natural generalization of graph isomorphism for multiple graphs. In this thesis we present fast algorithms for graph isomorphism and graph isomorphism query processing. First, we present a new approach to graph isomorphism, which is the framework of pairwise color refinement and efficient backtracking. Within the framework, we introduce three efficient techniques, which together lead to a much faster and scalable algorithm for graph isomorphism. Experiments on real-world datasets show that our algorithm outperforms state-of-the-art solutions by up to several orders of magnitude in terms of running time. Second, We develop an efficient algorithm for graph isomorphism query processing. We use a two-level index using degree sequences and color-label distributions. Experimental results on real datasets show that our algorithm is orders of magnitude faster than the state-of-the-art algorithms in terms of index construction time, and it runs faster than existing algorithms in terms of query processing time as the graph sizes increase.그래프 동형 문제는 소셜 네트워크 서비스, 생물정보학, 화학정보학 등등 다양한 응용 분야에서 그래프 분석을 위해 다루고 있는 핵심 문제이다. 실생활에서 다루는 그래프 데이터의 크기가 커져 감에 따라, 대용량의 그래프를 처리할 수 있는 그래프 동형 알고리즘의 필요성이 높아지고 있다. 그러나 현재 존재하는 그래프 동형 알고리즘들은 대용량의 그래프에 대해서 시간 혹은 공간 측면에서 한계를 보여준다. 응용 분야 중에서는 여러 개의 그래프들 중에서 하나의 쿼리 그래프와 동형인 그래프를 모두 찾는 문제, 즉 그래프 동형 쿼리 프로세싱을 종종 요구하기도 한다. 본 논문에서는 대용량의 실제 그래프 데이터에 대해서 그래프 동형 문제와 그래프 동형 쿼리 프로세싱 문제를 빠르게 푸는 알고리즘들을 제안한다. 첫 번째로, 본 논문에서는 그래프 동형 문제를 위한 빠르고 확장성 있는 알고리즘을 제안한다. 이를 위해 쌍별 색 개선(pairwise color refinement)과 효율적인 백트래킹으로 구성된 프레임워크를 소개한다. 이 프레임워크 내에서 세 가지 효율적인 테크닉을 사용한다. 실제 그래프 데이터에 대한 실험을 통해 본 알고리즘이 현존하는 가장 빠른 알고리즘들보다 평균 수천 배 빠름을 보였다. 두 번째로, 본 논문에서는 그래프 동형 쿼리 프로세싱을 위한 효율적인 알고리즘을 개발한다. 본 알고리즘은 차수열과 색-레이블 분포를 이용한 인덱스를 이용한다. 실제 그래프 데이터에 대한 실험을 통해 본 알고리즘이 현존하는 알고리즘들보다 인덱싱 시간에서는 항상 평균 수천 배 빠르고, 쿼리 처리 시간에서는 중$\cdot$대용량의 그래프들에 대해서 평균 수십 배 빠르게 동작하는 것을 보였다.1. Introduction 1 1.1. Background 1 1.2. Organization 3 2. Preliminaries 4 2.1. Notation 4 2.2. Problem Definitions 6 2.3. Related Work 7 3. Graph Isomorphism 9 3.1. Algorithm Overview 12 3.2. Pairwise Color Refinement and Binary Cell Mapping 13 3.3. Compressed Candidate Space 16 3.4. Backtracking and Partial Failing Sets 21 3.5. Performance Evaluation 31 3.5.1. Comparing with Existing Solutions 35 3.5.2. Effectiveness of Individual Techniques 39 3.5.3. Analysis with Varying Degrees of Similarity 42 3.5.4. Sensitivity Analysis 46 4. Graph Isomorphism Query Processing 48 4.1. Canonical Coloring 51 4.2. Index Construction 56 4.3. Query Processing 59 4.4. Performance Evaluation 63 4.4.1. Varying Number of Hops 67 4.4.2. Varying Number of Data Graphs 74 5. Conclusion 78 5.1. Summary 78 5.2. Future Directions 79 요약 95박

Lateral Signals in Piezoresponse Force Microscopy at Domain Boundaries of Ferroelectric Crystals

In piezoresponse force microscopy a lateral signal at the domain boundaries is occasionally observed. In recent years, a couple of experiments have been reported and varying explanations for the origin of this lateral signal have been proposed. Additionally, elaborated theoretical modeling for this particular issue has been carried out. Here we present experimental data obtained on different crystallographic cuts of $\rm LiNbO_3$, $\rm BaTiO_3$, and $\rm KTiOPO_4$ single crystals. We could thereby rule out some of the explanations proposed so far, introduce another possible mechanism, and quantitatively compare our results to the existing modeling

An evaluation of LiDAR and optical satellite data for the measurement of structural attributes in British upland conifer plantation forestry

This study evaluates the ability of LiDAR, IKONOS and Landsat ETM+ data to provide estimates of forest structure in British upland conifer plantations. Little use has so far been made of these technologies in the UK, whereas in some other countries remote sensing has become integral to forest management systems. The aim of this thesis is to demonstrate the application of the selected remote sensing systems to provide up-to- date and accurate information on key forest variables such as tree height, volume and density. Two upland conifer areas, located in south-west Scotland and north-east England, were used to develop and validate the regression models used to estimate these forest variables. The ability of LiDAR to provide an accurate measurement of the ground and canopy surfaces was investigated in densely stocked plantations, typical for commercial forestry in the U.K. The results show that, despite the dense nature of the forest canopy, sufficient laser pulses penetrate through to the ground to generate an accurate Digital Terrain Model (DTM). Provided that the ground surface is accurately defined, a point density of 2 returns/m(^2) will enable measurement of tree height to be made. LiDAR-derived top heights were found to be as accurate as field-based measurements (RMSE of 0.57 m). LiDAR-derived top height is easily integrated with established Forestry Commission models to provide volume estimations. Tree density is not accurately estimated using LiDAR data (RMSE of 434 trees/ha). Results strongly suggest that predictive equations developed for top height can be transferred to other conifer forests. Furthermore, the relationship between field-measured top height and laser-derived top height appears to be stable across different conifer species. LiDAR data can be used to identify tree species in pure and mixed stands. Two methods were developed: the first used summary measures based on the laser height distribution and the second the near infrared intensity. These measures when mapped spatially can be used to classify areas by species and to identify areas of anomalous growth and wind damage. At a larger spatial scale. Landsat ETM+ and IKONOS data can provide height estimates up to the point of canopy closure (approximately 10 m). LiDAR-derived height can be used in place of field-based measurements to drive reflectance-based models to estimate height from optical satellite data. The methods developed are transferable to other conifer forests that are managed in a similar way. The results from this thesis show that LİDAR, IKONOS and Landsat ETM+ data provide valuable and complementary information at a_ range of scales and can assist managers to make more informed resource management decisions

Identification of Bacteria in Fresh Vegetables from The Traditional Market of Mataram City

Indonesia is very rich in potential for vegetable cultivation. Vegetables contain a lot of vitamins and minerals. Therefore, people prefer to eat vegetables in a fresh state either as salads or fresh vegetables. However, contamination of pathogenic bacteria is much greater both at the farmer and trader levels. Therefore this study aims to determine the feasibility of consumption and identify bacteria in fresh vegetables in the traditional market of Mataram City. Samples in the form of lettuce, cucumber, cabbage, and long beans were taken from Pagesangan, Kebon Roek, Gunung Sari, and Bertais markets, respectively. The existence of bacteria were detected using traditional method by inoculating samples in agar cultures followed by biochemical testing and Gram staining. Species of bacteria that can be identified from samples are Enterobacter cloacae, Bhanhamella catarrhalis, E-coli, Staphylococus sapropyticus, and Aeromonas hydrophila. Based on the data, long beans from the Bertais market and lettuce from the Pagesangan, Kebon Roek, and Gunung Sari markets are not suitable for consumption because the TPC yield exceeds the consumption quality standard of 105-106 CFU/g