Similarity models for internet host location

Geolocation techniques aim at determining the geographic location of an Internet host based on its IP address. Currently, measurement-based geolocation techniques disregard the buffering delays that may be introduced at each hop along the path taken by probe packets. To fill this gap, we propose the GeoBuD (Geolocation using Buffering Delay estimation) approach. Although the network delay and the geographic distance between two Internet hosts have been shown to be related to some extent, leveraging buffering delay estimation at each hop for geolocation purposes is challenging for two reasons. First, correctly estimating the buffering delay at intermediate hops along a traceroute path for geolocation purposes depends on the accurate estimation of the geolocation of the intermediate routers. Second, even given an a priori knowledge of the location of the routers, estimating the buffering delays is difficult due to the coarse-grained information provided by delay measurements. Relying on traceroute measurements, we show that leveraging buffering delay estimation improves accuracy in the measurement-based geolocation of Internet hosts as well as the confidence that the geolocation service associates to each estimation.Keywordsgeolocationbuffering delay estimationtraceroutemultilateration

In this paper, we ask whether it is possible to build an IP address to geographic location mapping service for Internet hosts. Such a service would enable a large and interesting class of location-aware applications. This is a challenging problem because an IP address does not inherently contain an indication of location.We present and evaluate three distinct techniques, collectively referred to as IP2Geo, for determining the geographic location of Internet hosts. The first technique, Geo Track, infers location based on the DNS names of the target host or other nearby network nodes. The second technique, GeoPing, uses network delay measurements from geographically distributed locations to deduce the coordinates of the target host. The third technique, GeoCluster, combines partial (and possibly inaccurate) host-to-location mapping information and BGP prefix information to infer the location of the target host. Using extensive and varied data sets, we evaluate the performance of these techniques and identify fundamental challenges in deducing geographic location from the IP address of an Internet host.

In this paper, we consider the problem of how to represent the locations of Internet hosts in a Cartesian coordinate system to facilitate estimation of network distances among arbitrary Internet hosts. We envision an infrastructure that consists of beacon nodes and provides the service of estimating network distance between pairs of hosts without direct delay measurement. We show that the principal component analysis (PCA) technique can effectively extract topological information from delay measurements between beacon hosts. Based on PCA, we devise a transformation method that projects the raw distance space into a new coordinate system of (much) smaller dimensions. The transformation retains as much topological information as possible and yet enables end hosts to determine their coordinates in the coordinate system. The resulting new coordinate system is termed as the Internet Coordinate System (ICS). As compared to existing work (e.g., IDMaps and GNP), ICS incurs smaller computation overhead in calculating the coordinates of hosts and smaller measurement overhead (required for end hosts to measure their distances to beacon hosts). Finally, we show via experiments with both real-life and synthetic data sets that ICS makes robust and accurate estimates of network distances, incurs little computational overhead, and its performance is not susceptible to the number of beacon nodes (as long as it exceeds a certain threshold) and the network topology.

We propose VoteGeo, an IoT-based voting approach, to verify the geographic location of the cloud hosts in moderately connected networks, where the correlation between the network delay and the distance is weak. We motive our work by showing that: 1) existing solutions, based on end-to-end delay measurement from a group of landmarks with known locations, are only workable when the relationship between the delay and the distance is strong, and 2) such landmark-based schemes are limited by landmark distribution and deployment costs. In our scheme, to enhance the verification accuracy, we develop a vote-based closest-shortest approach to determine the location of the target cloud host, which utilizes the adjacent landmarks with the shortest delays. In order to reduce deployment costs, we adopt random IoT devices (i.e., IP cameras) as landmarks, which are widely distributed and considerable. To reduce the measurement cost, we design a two-level probing method to determine the geographic location of the target cloud hosts step by step, eventually to the city-level. We introduce a delay threshold method, which does not rely on the IP address of the target cloud hosts, to defend against the middlebox-bypass attacks and the delay attacks (i.e., delay-shortening attacks and delay-adding attacks). The evaluation results show that VoteGeo outperforms existing schemes such as GeoGet [1] and CBG [2].

R&D Subsidiaries’ Innovative Performance 'Revisited' - A Multilevel Approach

Network measurement based modeling and optimization for IP geolocation

The present study describes a new species of myxosporean, Ellipsomyxa ariusi sp. nov., infecting the gallbladder of the threadfin sea catfish Arius arius (Hamilton, 1822). E. ariusi sp. nov. is characterized by bivalvular, ellipsoid or elongate-oval myxospores with smooth spore valves and a straight suture, arranged at an angle to the longitudinal spore axis. Mature myxospores measured 10.1 ± 0.8 µm in length, 6.8 ± 0.5 µm in width and 7.7 ± 0.7 µm in thickness. Polar capsules are equal in size and oval to pyriform in shape. They are positioned at an angle to the longitudinal myxospore axis and open in opposite directions. Polar capsules measured 2.8 ± 0.3 µm in length and 2.5 ± 0.4 µm in width; polar filaments formed 4-5 coils, and extended to 32.2 ± 2.1 µm in length. Monosporic and disporic plasmodial stages attached to the wall of gallbladder. Molecular analysis of the type specimen generated a 1703 bp partial SSU rDNA sequence (MN892546), which was identical to the isolates from 3 other locations. In phylogenetic analyses, genus Ellipsomyxa appeared monophyletic and E. ariusi sp. nov. occupied an independent position in maximum likelihood and Bayesian inference trees with high bootstrap values. The overall prevalence of infection was 54.8% and multiway ANOVA revealed that it varied significantly with location, year, season, sex and size of the fish host. Histopathological changes associated with E. ariusi sp. nov. infection included swelling, vacuolation and detachment of epithelial layer, reduced mucus production and altered consistency and colour of bile. Based on the morphologic, morphometric and molecular differences with known species of Ellipsomyxa, and considering differences in host and geographic locations, the present species is treated as new and the name Ellipsomyxa ariusi sp. nov. is proposed.

Behavioral mechanisms of parasitic wasps for searching concealed insect hosts

International management scholars are paying increasing attention to the internationalization of service firms from emerging markets, but empirical research on the challenges facing such firms remains scarce. This study examines how emerging market banks (EMBs) cope with the liability of emergingness. To this end, we conducted exploratory, qualitative interviews with Brazilian and Chinese bankers. We found that the liability may hamper the ability of EMBs to engage in institutional isomorphism in order to effectively embed themselves into host locations. The results reveal that liability of emergingness is a problem, particularly for Chinese banks whose internationalization links with the Belt Road Initiative—national strategy to support the Chinese firms go global. The findings indicate that a major problem is that senior managers in the home countries fail to understand the importance of differences between home and host country institutional systems. The low level of autonomy granted to subsidiary managers, which arises from this lack of understanding on the part of their headquarters, hinders the ability of subsidiaries to effectively engage in normative and mimetic isomorphism to embed into host location institutional systems. The study also highlights differences in how Brazilian and Chinese banks might address this challenge.KeywordsAdvanced economiesEmerging market banksHeadquartersInternationalization strategyLiability of emergingness

This paper analyzes how the AS's geographic locations and transmission distances affect on Internet's stability. In contrast to the traditional studies focusing on the future AS network which based on nowadays, this paper emphasizes particularly on the change of AS network's performance under the effect of the economic adjusting or the technology innovation to help make adjusting measures and to lead the technological trend. A double-deck network model of geographic hypergraph and AS network is presented to simulate the geographic locations, which is not reflected in traditional models. The simulate results of our model show that Internets stability ascends with the increase of transmission distances. However, if AS's geographic locations are random, the transmission distances has no obvious effects on Internets stability.

Efficient measurement of round-trip link delays in software-defined networks

Measurement and Prediction of Communication Delays in Myrinet Networks

Geoeconomics has attracted sustained attention in recent years, but the role of independent directors’ geographic distance in investment efficiency remains unexplored. We explore the governance effects of independent directors from a geographic location perspective. Specifically, the Great Circle Distance Formula is employed to calculate the geographic distance between the independent directors and the enterprise. Then, we measure the inefficient investment. Using a detailed sample in the Chinese market from 2009 to 2018, we find that geographic distance is not conducive to the functioning of independent directors and that there is a positive relationship between independent directors’ geographic distance and inefficient investment. The coefficients are robust to multiple robustness checks. In addition, the positive effect of independent directors’ geographic distance on inefficient investment will increase (become more positive) when there is no high-speed rail and the marketisation process is low in the enterprise’s location. Mechanism tests show that geographic distance does affect inefficient investment by inhibiting independent directors’ access to information as well as their reputation. Our results have important implications for investment policy and corporate governance.

Given an IP address, it is a challenging task to obtain its geographic location. Besides approaches which associate coordinates with IP addresses in a predominantly static way, there are also measurement based approaches that exploit the correlation between the propagation delay of signals and round trip times of probe packets. We analyze multiple approaches solely based on delay measurements, i. e. without the use of third-party knowledge, and obtain mean errors of just under 100 km. In this paper, we propose a new model for IP geolocation which combines the strengths of different previous techniques and reduces IP geolocation to the problem of finding equilibrium points in a spring system. Our approach, called Spring-Based Geolocation (SBG), is able to reduce the mean error to less than 75km in our experiments without adding significant complexity. In fact, our model allows for additional data sources in a natural way, which has the potential to further improve results.

In network measurement, sliding window measurement has the advantage of providing recent and timely measurement results. Recently, sketches have become the most popular method of conducting flow-level network measurements due to their favorable trade-off between small memory overhead and high measurement accuracy. However, it remains a challenge that no current sketches are able to support unbiased estimation toward flow size measurement, which can improve the performance of tasks including network diagnoses, delay measurement and heavy hitter detection. In this paper, we propose the first work that achieves unbiased flow size measurement in sliding windows, namely <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Unbiased Cleaning sketch (UC sketch)</b> . The key technique of the UC sketch is <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Unbiased Cleaning</i> which can remove outdated keys from the sliding windows in a balanced way. Besides, we significantly reduce the variance of flow size by two optimization techniques, namely <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Linear Scaling</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Column Randomizing</i> . To prove the result, we conduct rigorous mathematical analysis and reasonable experiments. All related source codes are open-sourced at Github anonymously.