5 research outputs found
<Articles>The Legitimacy of the Rule of the Muzaffarids : Changes in Policy during the Reign of Mubariz al-Din Muhammad
No full textイル・ハーン朝末期、ヤズドの支配権を授与されたムザッファル朝の創始者 Mubariz al-Din Muhammad は、Abu Sa id 死後の混乱期において、ヤズドの有力者であるニザーム家に関わる人々を経済的保護によって優遇し、ケルマーン地方進出以降には、ウラマーの側も積極的に王朝の支配を支持する姿勢をとるようになる。こうして Mubariz al-Din は徐々に支配に対する都市住民の支持を獲得したが、シーラーズ征服後、さらなる遠征を前にして、新たに支配領域に組み込んだファールス地方に対し、これまで以上に支配者としての立場を明確にする必要に迫られた。このため、カイロのアッバース朝カリフに対するバイアを行い、その後世俗権力者「スルタン」としての地位とカリフの持つ宗教的権限をも主張するようになった。こうした支配者としての権威の変遷は、モンゴルの影響が急速に薄れていくイランにおいて、新たなる君主像が生まれつつあったことを示しているといえよう。After the death of the last de facto Il Khan, Aba Said, in 1335, influential Mongol amirs seated descendants of Chingiz Khan as puppet rulers in a struggle for power. At first, local Iranian dynastic regimes, which had been established under the Il Khanid dynasty, recognized the authority of such puppet khans, but later denied the authority of the Mongols. Although a large number of studies have been made on how regional Iranian regimes won support for their rule, little research has been devoted to the Muzaffarids, one of the local regimes established during the Il Khanid period. Therefore, I wish to show in this study the process of the establishment of the legitimacy of the rule of Mubariz al-Din Muhammad, the founder of the dynasty. Muzaffar, the father of Mubariz al-Din, served several of the Il Khanid rulers, and was conferred the post of overseeing the roads (tutghaul) in Yazd district. After his father's death, Mubariz al-Din inherited the post and was then given the title of governor of Yazd by Aba Sa'id in 1318. Because the Muzaffarids were descended from an Arab family who had migrated to Yazd during the Mongol invasion, they had no relations with the people of Yazd. It seems likely that without the support of the Il Khan, Mubariz al-Din could not have attained legitimacy to rule Yazd from the first. After obtaining the right to rule in Yazd, Mubariz al-Din actively started to develop relations with powerful figures in Yazd, especially a family of the Sayyids known as the Nizam, giving them economic support in the form of appointments to offices. Moreover, as Mubariz al-Din conquered the Kirman district, the 'ulama came to play an important role when he made war or concluded peace with the nomadic tribes of Mongols in the district. In this way, we may say that he won the support of city dwellers for his own rule, but he made no effort to make outward display of his position as ruler at the time. After Mubariz al-Din captured Shiraz in 1353, he had to establish the legitimacy of his rule over the newly gained Fars district in order to further his military operations. Consequently, he chose to swear an oath of loyalty (bay'a) to the 'Abbasid Caliph in Cairo. Thereafter, Mubariz al-Din came to assert not only his status as secular ruler, Sultan, but the authority of a religious leader as well. Judging from the changes policy during the reign of Mubariz al-Din, it appears that both secular power and religious authority were required by a ruler in order to establish the legitimacy of rule in Iran where the authority of the Chingizid had rapidly faded
VPR-Bench: An Open-Source Visual Place Recognition Evaluation Framework with Quantifiable Viewpoint and Appearance Change
Get PDFVisual place recognition (VPR) is the process of recognising a previously visited place using visual information, often under varying appearance conditions and viewpoint changes and with computational constraints. VPR is related to the concepts of localisation, loop closure, image retrieval and is a critical component of many autonomous navigation systems ranging from autonomous vehicles to drones and computer vision systems. While the concept of place recognition has been around for many years, VPR research has grown rapidly as a field over the past decade due to improving camera hardware and its potential for deep learning-based techniques, and has become a widely studied topic in both the computer vision and robotics communities. This growth however has led to fragmentation and a lack of standardisation in the field, especially concerning performance evaluation. Moreover, the notion of viewpoint and illumination invariance of VPR techniques has largely been assessed qualitatively and hence ambiguously in the past. In this paper, we address these gaps through a new comprehensive open-source framework for assessing the performance of VPR techniques, dubbed “VPR-Bench”. VPR-Bench (Open-sourced at: https://github.com/MubarizZaffar/VPR-Bench) introduces two much-needed capabilities for VPR researchers: firstly, it contains a benchmark of 12 fully-integrated datasets and 10 VPR techniques, and secondly, it integrates a comprehensive variation-quantified dataset for quantifying viewpoint and illumination invariance. We apply and analyse popular evaluation metrics for VPR from both the computer vision and robotics communities, and discuss how these different metrics complement and/or replace each other, depending upon the underlying applications and system requirements. Our analysis reveals that no universal SOTA VPR technique exists, since: (a) state-of-the-art (SOTA) performance is achieved by 8 out of the 10 techniques on at least one dataset, (b) SOTA technique in one community does not necessarily yield SOTA performance in the other given the differences in datasets and metrics. Furthermore, we identify key open challenges since: (c) all 10 techniques suffer greatly in perceptually-aliased and less-structured environments, (d) all techniques suffer from viewpoint variance where lateral change has less effect than 3D change, and (e) directional illumination change has more adverse effects on matching confidence than uniform illumination change. We also present detailed meta-analyses regarding the roles of varying ground-truths, platforms, application requirements and technique parameters. Finally, VPR-Bench provides a unified implementation to deploy these VPR techniques, metrics and datasets, and is extensible through templates
Visual Place Recognition for Autonomous Robots
Get PDFAutonomous robotics has been the subject of great interest within the research community over the past few decades. Its applications are wide-spread, ranging from health-care to manufacturing, goods transportation to home deliveries, site-maintenance to construction, planetary explorations to rescue operations and many others, including but not limited to agriculture, defence, commerce, leisure and extreme environments. At the core of robot autonomy lies the problem of localisation, i.e, knowing where it is and within the robotics community, this problem is termed as place recognition. Place recognition using only visual input is termed as Visual Place Recognition (VPR) and refers to the ability of an autonomous system to recall a previously visited place using only visual input, under changing viewpoint, illumination and seasonal conditions, and given computational and storage constraints.
This thesis is a collection of 4 inter-linked, mutually-relevant but branching-out topics within VPR: 1) What makes a place/image worthy for VPR?, 2) How to define a state-of-the-art in VPR?, 3) Do VPR techniques designed for ground-based platforms extend to aerial platforms? and 4) Can a handcrafted VPR technique outperform deep-learning-based VPR techniques? Each of these questions is a dedicated, peer-reviewed chapter in this thesis and the author attempts to answer these questions to the best of his abilities.
The worthiness of a place essentially refers to the salience and distinctiveness of the content in the image of this place. This salience is modelled as a framework, namely memorable-maps, comprising of 3 conjoint criteria: a) Human-memorability of an image, 2) Staticity and 3) Information content. Because a large number of VPR techniques have been proposed over the past 10-15 years, and due to the variation of employed VPR datasets and metrics for evaluation, the correct state-of-the-art remains ambiguous. The author levels this playing field by deploying 10 contemporary techniques on a common platform and use the most challenging VPR datasets to provide a holistic performance comparison. This platform is then extended to aerial place recognition datasets to answer the 3rd question above. Finally, the author designs a novel, handcrafted, compute-efficient and training-free VPR technique that outperforms state-of-the-art VPR techniques on 5 different VPR datasets
Sequence-Based Filtering for Visual Route-Based Navigation: Analyzing the Benefits, Trade-Offs and Design Choices
Get PDFVisual Place Recognition (VPR) is the ability to correctly recall a previously visited place using visual information under environmental, viewpoint and appearance changes. An emerging trend in VPR is the use of sequence-based filtering methods on top of single-frame-based place matching techniques for route-based navigation. The combination leads to varying levels of potential place matching performance boosts at increased computational costs. This raises a number of interesting research questions: How does performance boost (due to sequential filtering) vary along the entire spectrum of single-frame-based matching methods? How does sequence matching length affect the performance curve? Which specific combinations provide a good trade-off between performance and computation? However, there is lack of previous work looking at these important questions and most of the sequence-based filtering work to date has been used without a systematic approach. To bridge this research gap, this paper conducts an in-depth investigation of the relationship between the performance of single-frame-based place matching techniques and the use of sequence-based filtering on top of those methods. It analyzes individual trade-offs, properties and limitations for different combinations of single-frame-based and sequential techniques. The experiments conducted in this study demonstrate the benefits of sequence-based filtering over the single-frame-based approach using various VPR techniques. We found that applying sequence-based filtering to a lightweight descriptor can enable higher VPR accuracy than state-of-the-art methods such as NetVLAD, while running in shorter time. For example, matching a sequence of 16 images, CALC descriptor outperforms NetVLAD on Campus Loop dataset while taking about 22% less time to perform VPR.Intelligent Vehicle
Provincial Demands for Self-rule and Shared-rule under the 18th Amendment in Pakistan: An Assessment
Get PDFThis study analyzes the development in the two basic concepts of federalism by Daniel Elazar: self-rule and shared rule in Pakistan, after the implementation of 18th amendment. These federal concepts would remain the main concern of the present study. This paper has analyzed the expansion as to what extent the 18th amendment has fulfilled the requirements of self-rule and shared rule in Pakistan. The two federal conceptions were the set parameters to approach the 18th constitutional amendment in Pakistan. This historical amendment has converted the entire federal political system to one decentralized and participatory. The federal system was highly centralized and less participatory before the amendment. It has redesigned and updated the entire federal setup. It is a provincial liability now to get an advantage of giving opportunities and enjoy proposed benefits set up by their historic demands by constitutional arrangements. It is recommended on the basis of the findings that federal and provincial authorities should keep the said changes and restore the real federal spirit of the constitution by exercising the proposed changes in the constitution on provincial demands by the federal government
