Hasil untuk "Asian. Oriental"

Karthekeyan Chandrasekaran, Siyue Liu, R. Ravi

Flows and colorings are disparate concepts in graph algorithms -- the former is tractable while the latter is intractable. Tutte introduced the concept of nowhere-zero flows to unify these two concepts. Jaeger showed that nowhere-zero flows are equivalent to cut-balanced orientations. Motivated by connections between nowhere-zero flows, cut-balanced orientations, Nash-Williams' well-balanced orientations, and postman problems, we study optimization versions of nowhere-zero flows and cut-balanced orientations. Given a bidirected graph with asymmetric costs on two orientations of each edge, we study the min cost nowhere-zero $k$-flow problem and min cost $k$-cut-balanced orientation problem. We show that both problems are NP-hard to approximate within any finite factor. Given the strong inapproximability result, we design bicriteria approximations for both problems: we obtain a $(6,6)$-approximation to the min cost nowhere-zero $k$-flow and a $(k,6)$-approximation to the min cost $k$-cut-balanced orientation. For the case of symmetric costs (where the costs of both orientations are the same for every edge), we show that the nowhere-zero $k$-flow problem remains NP-hard and admits a $3$-approximation.

Jieting Zhao, Hanjing Ye, Yu Zhan et al.

Reliable Human Orientation Estimation (HOE) from a monocular image is critical for autonomous agents to understand human intention. Significant progress has been made in HOE under full observation. However, the existing methods easily make a wrong prediction under partial observation and give it an unexpectedly high confidence. To solve the above problems, this study first develops a method called Part-HOE that estimates orientation from the visible joints of a target person so that it is able to handle partial observation. Subsequently, we introduce a confidence-aware orientation estimation method, enabling more accurate orientation estimation and reasonable confidence estimation under partial observation. The effectiveness of our method is validated on both public and custom-built datasets, and it shows great accuracy and reliability improvement in partial observation scenarios. In particular, we show in real experiments that our method can benefit the robustness and consistency of the Robot Person Following (RPF) task.

Jannick Borowitz, Ernestine Großmann, Christian Schulz

A (fully) dynamic graph algorithm is a data structure that supports edge insertions, edge deletions, and answers certain queries that are specific to the problem under consideration. There has been a lot of research on dynamic algorithms for graph problems that are solvable in polynomial time by a static algorithm. However, while there is a large body of theoretical work on efficient dynamic graph algorithms, a lot of these algorithms were never implemented and empirically evaluated. In this work, we consider the fully dynamic edge orientation problem, also called fully dynamic $Δ$-orientation problem, which is to maintain an orientation of the edges of an undirected graph such that the out-degree is low. If edges are inserted or deleted, one may have to flip the orientation of some edges in order to avoid vertices having a large out-degree. While there has been theoretical work on dynamic versions of this problem, currently there is no experimental evaluation available. In this work, we close this gap and engineer a range of new dynamic edge orientation algorithms as well as algorithms from the current literature. Moreover, we evaluate these algorithms on real-world dynamic graphs. The best algorithm considered in this paper in terms of quality, based on a simple breadth-first search, computes the optimum result on more than 90% of the instances and is on average only 2.4% worse than the optimum solution.

Long Xu, Ilia Tutunnikov, Yehiam Prior et al.

We theoretically consider the phenomenon of field-free long-lasting orientation of symmetric-top molecules ionized by two-color laser pulses. The anisotropic ionization produces a significant long-lasting orientation of the surviving neutral molecules. The degree of orientation increases with both the pulse intensity and, counterintuitively, with the rotational temperature. The orientation may be enhanced even further by using multiple delayed two-color pulses. The long-lasting orientation may be probed by even harmonic generation or by Coulomb-explosion-based methods. The effect may enable the study of relaxation processes in dense molecular gases, and may be useful for molecular guiding and trapping by inhomogeneous fields.

Or Kedar, Jake P. Solomon

Let $L\subset X$ be a not necessarily orientable relatively $Pin$ Lagrangian submanifold in a symplectic manifold $X$. We construct a family of cyclic unital curved $A_\infty$ structures on differential forms on $L$ with values in the local system of graded non-commutative rings given by the tensor algebra of the orientation local system of $L$. The family of $A_\infty$ structures is parameterized by the cohomology of $X$ relative to $L$ and satisfies properties analogous to the axioms of Gromov-Witten theory. On account of the non-orientability of $L,$ the evaluation maps of moduli spaces of $J$-holomorphic disks with boundary in $L$ may not be relatively orientable. To deal with this problem, we use recent results on orientor calculus.

K. S. Ajish Kumar, Birenjith Sasidharan, K. S. Sudeep

Assignment of one of the two possible directions to every edge of an undirected graph $G=(V,E)$ is called an orientation of $G$. The resulting directed graph is denoted by $\overrightarrow{G}$. A strong orientation is one in which every vertex is reachable from every other vertex via a directed path. The diameter of $\overrightarrow{G}$, i.e., the maximum distance from one vertex to another, depends on the particular orientation. The minimum diameter among all possible orientations is called the oriented diameter $\overrightarrow{\text{diam}}(G)$ of $G$. Let $n,k$ be two integers with $1 \leq k < n$. In the realm of interconnection networks of processing elements, an $(n,k)$-star graph $S_{n,k}$ offers a topology that circumvents the lack of scalability of $n$-star graphs $S_n$. In this paper, we present a strong orientation for $S_{n,k}$ that combines approaches suggested by Cheng and Lipman [Journal of Interconnection Networks (2002)] for $S_{n,k}$ with the one proposed by Fujita [The First International Symposium on Computing and Networking (CANDAR 2013)] for $S_n$. Next, we propose a distributed routing algorithm for $\overrightarrow{S_{n,k}}$ inspired by an algorithm proposed by Kumar, Rajendraprasad and Sudeep [Discrete Applied Mathematics (2021)] for $\overrightarrow{S_n}$. With the aid of both the orientation scheme and the routing algorithm, we show that $\overrightarrow{\text{diam}}(S_{n,k}) \leq \lfloor \frac{n+k}{2} \rfloor + 2k + 6 - δ(n,k)$ where $δ(n,k)$ is a non-negative function. The function $δ(n,k)$ takes on values $2k-n$, $0$, and $\left\lfloor \frac{n-3k}{2} \right\rfloor$ respectively for three disjoint intervals $k>\frac{n}{2}$, $\frac{n}{3} < k \leq \frac{n}{2}$ and $k\leq \frac{n}{3}$. For every value of $n$, $k$, our upper bound performs better than all known bounds in literature.

Yalan Qin, Guorui Feng, Hanzhou Wu et al.

Deep Convolutional Neural Networks (DCNNs) are capable of obtaining powerful image representations, which have attracted great attentions in image recognition. However, they are limited in modeling orientation transformation by the internal mechanism. In this paper, we develop Orientation Convolution Networks (OCNs) for image recognition based on the proposed Landmark Gabor Filters (LGFs) that the robustness of the learned representation against changed of orientation can be enhanced. By modulating the convolutional filter with LGFs, OCNs can be compatible with any existing deep learning networks. LGFs act as a Gabor filter bank achieved by selecting $ p $ $ \left( \ll n\right) $ representative Gabor filters as andmarks and express the original Gabor filters as sparse linear combinations of these landmarks. Specifically, based on a matrix factorization framework, a flexible integration for the local and the global structure of original Gabor filters by sparsity and low-rank constraints is utilized. With the propogation of the low-rank structure, the corresponding sparsity for representation of original Gabor filter bank can be significantly promoted. Experimental results over several benchmarks demonstrate that our method is less sensitive to the orientation and produce higher performance both in accuracy and cost, compared with the existing state-of-art methods. Besides, our OCNs have few parameters to learn and can significantly reduce the complexity of training network.

Jasine Babu, Deepu Benson, Deepak Rajendraprasad et al.

An orientation of an undirected graph $G$ is an assignment of exactly one direction to each edge of $G$. The oriented diameter of a graph $G$ is the smallest diameter among all the orientations of $G$. The maximum oriented diameter of a family of graphs $\mathscr{F}$ is the maximum oriented diameter among all the graphs in $\mathscr{F}$. Chvátal and Thomassen [JCTB, 1978] gave a lower bound of $\frac{1}{2}d^2+d$ and an upper bound of $2d^2+2d$ for the maximum oriented diameter of the family of $2$-edge connected graphs of diameter $d$. We improve this upper bound to $ 1.373 d^2 + 6.971d-1 $, which outperforms the former upper bound for all values of $d$ greater than or equal to $8$. For the family of $2$-edge connected graphs of diameter $3$, Kwok, Liu and West [JCTB, 2010] obtained improved lower and upper bounds of $9$ and $11$ respectively. For the family of $2$-edge connected graphs of diameter $4$, the bounds provided by Chvátal and Thomassen are $12$ and $40$ and no better bounds were known. By extending the method we used for diameter $d$ graphs, along with an asymmetric extension of a technique used by Chvátal and Thomassen, we have improved this upper bound to $21$.

M. Mášek, Michal Motyka, Dominik Kusy et al.

We synthesize the evidence from molecular phylogenetics, extant distribution, and plate tectonics to present an insight in ancestral areas, dispersal routes and the effectiveness of geographic barriers for net-winged beetle tribes (Coleoptera: Lycidae). Samples from all zoogeographical realms were assembled and phylogenetic relationships for ~550 species and 25 tribes were inferred using nuclear rRNA and mtDNA markers. The analyses revealed well-supported clades at the rank of tribes as they have been defined using morphology, but a low support for relationships among them. Most tribes started their diversification in Southeast and East Asia or are endemic to this region. Slipinskiini and Dexorini are Afrotropical endemics and Calopterini, Eurrhacini, Thonalmini, and Leptolycini remained isolated in South America and the Caribbean after their separation from northern continents. Lycini, Calochromini, and Erotini support relationships between the Nearctic and eastern Palearctic faunas; Calochromini colonized the Afrotropical realm from East Asia and Metriorrhynchini Afrotropical and Oriental realms from the drifting Indian subcontinent. Most tribes occur in the Oriental and Sino-Japanese realms, the highest alpha-taxonomic diversity was identified in Malesian tropical rainforests. The turn-over at zoogeographical boundaries is discussed when only short distance over-sea colonization events were inferred. The lycid phylogeny shows that poor dispersers can be used for reconstruction of dispersal and vicariance history over a long time-span, but the current data are insufficient for reconstruction of the early phase of their diversification.

David S. Roh, Betsy Huang

S. Athreya, R. Ackermann

In their seminal works on postcolonialism, Edward Saïd (in Orientalism) and V.Y. Mudimbe (in The Idea of Africa) proposed that Asia and Africa, respectively, were constructs created around the notion of their otherness. Both regions were viewed as infantile, primitive, and homogenous entities that fell outside the domain of civilized (i.e. Western) humanity. These constructs shaped scientific perceptions of both continents over the course of several centuries and have continued to be operative over the last 100 years following the discovery of fossil human ancestors, particularly within the narratives of recent human origins. Here we reflect on these narratives, both in the early days of the discoveries and more recently, in the context of the othered identities of the continents more broadly. We argue that a colonialist socio-political framework has shaped the science of human origins since its inception, and that this has negatively affected the quality of this endeavour. Existing phylogenies cannot be divorced from those ideologies—even today. Indeed, while the details of human origins (e.g. when, where, who) have changed radically over time, the narrative that emerged always left one group in control, and marginalised non-Western lands and their peoples, leaving the ordering of superior and inferior more or less unchanged through the history of the discipline. More informed models of human evolution cannot be constructed until the community of voices constructing them is reworked to be more inclusive of many worldviews.

J. Eberle, S. Fabrizi, P. Lago et al.

David S. Roh, Betsy Huang, G. A. Niu

What will the future look like? To judge from many speculative fiction films and books, from Blade Runner to Cloud Atlas, the future will be full of cities that resemble Tokyo, Hong Kong, and Shanghai, and it will be populated mainly by cold, unfeeling citizens who act like robots. Techno-Orientalism investigates the phenomenon of imagining Asia and Asians in hypo- or hyper-technological terms in literary, cinematic, and new media representations, while critically examining the stereotype of Asians as both technologically advanced and intellectually primitive, in dire need of Western consciousness-raising. The collection's fourteen original essays trace the discourse of techno-orientalism across a wide array of media, from radio serials to cyberpunk novels, from Sax Rohmer's Dr. Fu Manchu to Firefly. Applying a variety of theoretical, historical, and interpretive approaches, the contributors consider techno-orientalism a truly global phenomenon. In part, they tackle the key question of how these stereotypes serve to both express and assuage Western anxieties about Asia's growing cultural influence and economic dominance. Yet the book also examines artists who have appropriated techno-orientalist tropes in order to critique racist and imperialist attitudes. Techno-Orientalism is the first collection to define and critically analyze a phenomenon that pervades both science fiction and real-world news coverage of Asia. With essays on subjects ranging from wartime rhetoric of race and technology to science fiction by contemporary Asian American writers to the cultural implications of Korean gamers, this volume offers innovative perspectives and broadens conventional discussions in Asian American Cultural studies.

Stefan Felsner, Daniel Heldt

We study Markov chains for $α$-orientations of plane graphs, these are orientations where the outdegree of each vertex is prescribed by the value of a given function $α$. The set of $α$-orientations of a plane graph has a natural distributive lattice structure. The moves of the up-down Markov chain on this distributive lattice corresponds to reversals of directed facial cycles in the $α$-orientation. We have a positive and several negative results regarding the mixing time of such Markov chains. A 2-orientation of a plane quadrangulation is an orientation where every inner vertex has outdegree 2. We show that there is a class of plane quadrangulations such that the up-down Markov chain on the 2-orientations of these quadrangulations is slowly mixing. On the other hand the chain is rapidly mixing on 2-orientations of quadrangulations with maximum degree at most 4. Regarding examples for slow mixing we also revisit the case of 3-orientations of triangulations which has been studied before by Miracle et al.. Our examples for slow mixing are simpler and have a smaller maximum degree, Finally we present the first example of a function $α$ and a class of plane triangulations of constant maximum degree such that the up-down Markov chain on the $α$-orientations of these graphs is slowly mixing.

S. Shih

The spectacular rise of China as a superpower perhaps only now compels us to recalibrate existing discourses of empire and postcoloniality, but China has been an empire in the modern sense since the mid–eighteenth century, when it conquered vast lands north and west of “China proper.” This history has been largely hidden from view because of two unacknowledged obsessions: the fetishization of Western empires over other empires and the prevailing discourse of Chinese victimhood at the hands of Western empires. The rise of China would not have caught so many by surprise if our vision had not been persistently clouded by our privileging of the oceanic (i.e., Western) mode of colonial expansion, which paradoxically centered the West as the most deserving object of critical attention and intellectual labor. It also would not have been a surprise if we had looked back at the Manchu conquests of inner Asia, which present-day China largely inherited and consolidated in a continuous colonial project. Postcolonial theory as we know it, particularly its critiques of orientalism, may prove irrelevant or even complicit when we consider how the positions of Chinese intellectuals critical of Western imperialism and orientalism easily slip into an unreflective nationalism, whose flip side may be a new imperialism.

Christina Klein

G. Chowdhry, Sheila Nair

M. Abreu, D. Labbate, F. Romaniello et al.

A graph $G$ is $1$-extendible if every edge belongs to at least one $1$-factor of $G$. Let $G$ be a graph with a $1$-factor $F$. Then an even $F$-orientation of $G$ is an orientation in which each $F$-alternating cycle has exactly an even number of edges directed in the same fixed direction around the cycle. In this paper, we examine the structure of 1-extendible graphs $G$ which have no even $F$-orientation where $F$ is a fixed $1$-factor of $G$. In the case of graphs of connectivity at least four and k-regular graphs for $k \geq 3$ we give a complete characterization.

P. Daly, T. Winter

Alexandr Savinov

The main goal of concept-oriented programming (COP) is describing how objects are represented and accessed. It makes references (object locations) first-class elements of the program responsible for many important functions which are difficult to model via objects. COP rethinks and generalizes such primary notions of object-orientation as class and inheritance by introducing a novel construct, concept, and a new relation, inclusion. An advantage is that using only a few basic notions we are able to describe many general patterns of thoughts currently belonging to different programming paradigms: modeling object hierarchies (prototype-based program-ming), precedence of parent methods over child methods (inner methods in Beta), modularizing cross-cutting con-cerns (aspect-oriented programming), value-orientation (functional programming). Since COP remains backward compatible with object-oriented programming, it can be viewed as a perspective direction for developing a simple and natural unified programming model.