Academic literature on the topic 'Xu shi shi'

This chapter focuses on Xu Xu’s fiction from the 1930s and 40s, providing analyses of his main short stories and novels from this period, demonstrating how Xu’s work transitioned from modernist experimentation to popular romances after his return from studies in France. Xu’s bestselling short stories and novels were often set abroad and featured exotic, otherworldly characters, such as ghosts, spies, pirates and gypsies. In many of these works, the cosmopolitan, rational and educated male protagonist encounters a mysterious, elusive, otherworldly woman. Eventually, the truth is revealed and the mysteries are uncovered, vindicating the modern outlook of the male narrator. With their references to traditional literature, abnormal psychology and sexual desire, such works frequently echo Shi Zhecun and Mu Shiying’s writings from a decade earlier, yet Xu’s writings are mainly escapist entertainment rather than an attack on rational modernity or the status of art in society.

Marco Lombardo of the Università degli Studi di Bologna devised (Adv. Synth. Catal. 2012, 354, 3428) a silyl-bridged hydroxyproline catalyst that mediated the enantioselective addition of 2 to cinnamaldehyde 1 to give 3. Yoann Coquerel and Jean Rodriguez of Aix Marseille Université showed (Adv. Synth. Catal. 2012, 354, 3523) that a hybrid epi-cinchonine catalyst directed the enantioselective and diastereoselective addition of the amide 4 to the nitro alkene 5 to give 6. Magnus Rueping of RWTH Aachen observed (Angew. Chem. Int. Ed. 2012, 51, 12864) that a chiral Brønsted acid mediated the diastereoselective and enantioselective formation of 9 by the addition of 8 to cyclopentadiene 7. Marco Bandini, also of the University of Bologna, combined (Chem. Sci. 2012, 3, 2859) organocatalysis with gold catalysis to effect the cyclization of 10 to 11. Min Shi of the Shanghai Institute of Organic Chemistry prepared (Chem. Commun. 2012, 48, 2764) the quaternary cyclic amino acid derivative 14 by adding 13 to the acceptor 12. Makoto Tokunaga of Kyushu University prepared (Org. Lett. 2012, 14, 6178) the ketone 17 by the hydrolytic enantioselective protonation of the enol ester 15. Hiyoshizo Kotsuki of Kochi University developed (Synlett 2012, 23, 2554) a dual catalyst combination that effectively mediated the enantioselective addition of malonate even to the congested acceptor 18. Yoshitaka Hamashima and Toshiyuki Kan of the University of Shizuoka established (Org. Lett. 2012, 14, 6016) a protocol for the enantioselective brominative cyclization of 21, readily available by the reductive alkylation of benzoic acid. Polycarbocyclic ring systems can also be prepared by organocatalysis. Ying-Chun Chen of Sichuan University tuned (J. Am. Chem. Soc. 2012, 134, 19942) cinchona-derived catalysts to selectively convert 23 into either exo (illustrated) or endo 25. Peng-Fei Xu of Lanzhou University developed (Angew. Chem. Int. Ed. 2012, 51, 12339) a supramolecular iminium catalyst for the intramolecular Diels-Alder cycloaddition of 26. In a spectacular illustration of the power of organocatalysis, Varinder K. Aggarwal of the University of Bristol dimerized (Nature 2012, 489, 278) succinaldehyde from the hydrolysis of commercial 28 directly to the unsaturated aldehyde 29. Diastereoselective conjugate addition led to prostaglandin F2α 30.

Yuan-tsung blended further into village life, getting to know more villagers and their survival kit. One of them, a woman cadre named Winter Plum, initiated her into the black market, where she could get better food from a drunken butcher. Old Xu, the ever so complaisant village head, surprised her with his bitter resentment against his higher-ups and his bitterness over the loss of his family’s cohesion caused by collectivization. Wimpy Gu, the reticent and meek assistant to Old Xu, relieved himself occasionally with violent, emotional outbursts. Old Hong, renowned locally as the gloriously demobilized soldier, or Glorious Demob, amazed her with his web of deceit and lies for the sake of manufacturing a fake bumper harvest.

In addition to working in the fields, Yuan-tsung helped in the office of Red Flag Village’s Party secretary, Old Xu, who eventually took her into his confidence. He let her in on an almost comical attempt to smuggle a fat pig past starving peasants, so that the Party bigwigs could feast on it. It opened her eyes to the corruption and shenanigans of village politics, which mirrored the state of affairs nationwide. Meanwhile it brought her close to the victims and she became their friend. One of them, Lotus Boy, talented and gentle, would soon die of starvation and political persecution.

Knowledge discovery in databases, commonly referred to as data mining, has attracted enormous research efforts from different domains such as databases, statistics, artificial intelligence, data visualization, and so forth in the past decade. Most of the research work in data mining such as clustering, association rules mining, and classification focus on discovering large patterns from databases (Ramaswamy, Rastogi, & Shim, 2000). Yet, it is also important to explore the small patterns in databases that carry valuable information about the interesting abnormalities. Outlier detection is a research problem in small-pattern mining in databases. It aims at finding a specific number of objects that are considerably dissimilar, exceptional, and inconsistent with respect to the majority records in an input database. Numerous research work in outlier detection has been proposed such as the distribution-based methods (Barnett & Lewis, 1994; Hawkins, 1980), the distance-based methods (Angiulli & Pizzuti, 2002; Knorr & Ng, 1998, 1999; Ramaswamy et al.; Wang, Zhang, & Wang, 2005), the density-based methods (Breuning, Kriegel, Ng, & Sander, 2000; Jin, Tung, & Han, 2001; Tang, Chen, Fu, & Cheung, 2002), and the clustering-based methods (Agrawal, Gehrke, Gunopulos, & Raghavan, 1998; Ester, Kriegel, Sander, & Xu, 1996; Hinneburg & Keim, 1998; Ng & Han, 1994; Sheikholeslami, Chatterjee, & Zhang, 1999; J. Zhang, Hsu, & Lee, 2005; T. Zhang, Ramakrishnan, & Livny, 1996).

Location-based services (LBS) are services that answer queries based on the locations with which the queries are associate; normally the locations where the queries are issued. With a variety of promising applications, such as local information access (e.g., traffic reports, news, and navigation maps) and nearest neighbor queries (e.g., finding the nearest restaurants) (Barbara, 1999; Ren & Dunham, 2000; D. L. Lee, Lee, Xu, & Zheng, 2002; W. C. Lee, Xu, & Zheng, 2004), LBS is emerging as an integral part of daily life. The greatest potential of LBS is met in a mobile computing environment, where users enjoy unrestricted mobility and ubiquitous information access. For example, a traveler could issue a query like “Find the nearest hotel with a room rate below $100” from a wireless portable device in the middle of a journey. To answer such a query, however, three major challenges have to be overcome: • Constrained Mobile Environments: Users in a mobile environment suffer from various constraints, such as scarce bandwidth, lowquality communication, frequent network disconnections, and limited local resources. These constraints pose a great challenge for the provision of LBS to mobile users. • Spatial Data: In LBS, the answers to a query associated with different locations may be different. That is, query results are dependent on spatial properties of queries. For a query bound with a certain query location, the query result should be relevant to the query as well as valid for the bound location. This requirement adds additional complexity to traditional data management techniques such as data placement, indexing, and query processing (D. L. Lee, 2002). • User Movement: The fact that a mobile user may change its location makes some tasks in LBS, such as query scheduling and cache management, particularly tough. For example, suppose that a mobile user issues a query “Find the nearest restaurant” at location A. If the query is not scheduled timely enough on the server, the user has moved to location B when he or she gets the answer R. However, R is no longer the nearest restaurant at location B. Caching has been a commonly used technique for improving data access performance in a mobile computing environment (Acharya, Alonso, Franklin, & Zdonik, 1995). There are several advantages for caching data on mobile clients: • It improves data access latency since a portion of queries, if not all, can be satisfied locally. • It helps save energy since wireless communication is required only for cache-miss queries. • It reduces contention on the narrow-bandwidth wireless channel and off-loads workload from the server; as such, the system throughput is improved. • It improves data availability in circumstances where clients are disconnected or weakly connected because cached data can be used to answer queries. However, as discussed above, the constrains of mobile computing environments, the spatial property of location-dependent data, and the mobility of mobile users have opened up many new research problems in client caching for LBS. This chapter discusses the research issues arising from caching of location-dependent data in a mobile environment and briefly describes several state-of-the-art solutions.

M-commerce (mobile commerce) applications have evolved out of e-commerce (electronic commerce) applications, riding on recent advancement in wireless communication technologies. Exploiting the most unique aspect inherent in m-commerce, namely, the mobility of customers, l-commerce (location-dependent m-commerce) applications have played an increasingly important role in the class of m-commerce applications. All e-commerce, m-commerce, and l-commerce applications rely on the provision of information retrieval and processing capability. L-commerce applications further dictate the maintenance of customer and service location information. Various database systems are deployed as the information source and repository for these applications, backed by efficient indexing mechanisms, both on regular data and location-specific data. Bean (2003) gave a good report on supporting Web-based e-commerce with XML, which could be easily extended to m-commerce. An m-commerce framework, based on JINI/XML and a workflow engine, was defined by Shih and Shim (2002). Customers can receive m-commerce services through the use of mobile devices such as pocket PCs, PDAs, or even smart phones. These mobile devices together with their users are often modeled as mobile clients. There are three types of entities central to m-commerce and l-commerce applications: mobile device, wireless communication, and database. In this article, we focus our discussion on mobile-client enabled database servers, often referred to as mobile databases. Mobile databases maintain information for the underlying m-commerce and l-commerce applications in which mobile devices serve as the hardware platform interfacing with customers, connected through wireless communication. Location is a special kind of composite data ranging from a single point, a line, a poly-line, to a shape defining an area or a building. In general, locations are modeled as spatial objects. The location of a static point of interest, such as a shop, is maintained in a database supporting spatial features and operations, often a spatial database (Güting, 1994). The location of a moving object, like a mobile customer, needs to be maintained in a moving object database (Wolfson, Sistla, Xu, Zhou, & Chamberlain, 1999), a database that supports efficient retrieval and update of object locations. To enable l-commerce, both spatial databases and moving object databases need to support location-specific query processing from mobile clients and location updates they generated. The two major types of data access requirements for a mobile database are data dissemination and dedicated data access. Data dissemination is preferred, since it can serve a large client population in utilizing the high bandwidth downlink channel to broadcast information of common interest, such as stock quotations, traffic conditions, or special events. On the other hand, dedicated data access is conveyed through uplink channels with limited bandwidth. To disseminate database items effectively, the selected set of hot database items can be scheduled as a broadcast disk (Acharya, Alonso, Franklin, & Zdonik, 1995). Proper indexes can be built to facilitate access to broadcast database items (Imielinski & Badrinath, 1994). Redundancy can be included in data (Leong & Si, 1995) and index (Tan & Ooi, 1998) to combat the unreliability of wireless communication.

Ryoichi Kuwano of Kyushu University showed (J. Am. Chem. Soc. 2008, 130, 808) that diastereomerically and enantiomerically pure pyrollidines such as 2 could be prepared by hydrogenation of the corresponding pyrrole. Victor S. Martín of Universidad de la Laguna found (Organic Lett. 2008, 10, 2349) that the stereochemical outcome of the pyrrolidine-forming Nicholas cyclization could be directed by the protecting group on the N. Jianbo Wang of Peking University established (J. Org. Chem. 2008, 73, 1971) a convenient route to diazo esters such as 6. N-H insertion led to the pyrrolidine, which Zhen-Jiang Xu of the Shanghai Institute of Organic Chemistry and Chi-Ming Che of the University of Hong Kong showed (Organic Lett. 2008, 10, 1529) could be reduced with high diastereoselectivity to the hydroxy ester 7. Alternatively, Professor Wang found that photochemical Wolff rearrangement of 6 delivered the pyrrolidone 8 . Martin J. Slater and Shiping Xie of GlaxoSmithKline optimized (J. Org. Chem. 2008, 73, 3094) the hydroquinine catalyzed enantioselective 3+2 cycloaddition of 9 and 10, leading to the pyrrolidine 11 with high diastereocontrol. Shu Kobayashi of the University of Tokyo developed (Adv. Synth. Cat. 2008, 350, 647) a practical protocol for the aza Diels-Alder construction of enantiomerically-pure piperidines such as 14 . Biao Yu of the Shanghai Institute of Organic Chemistry cyclized (Tetrahedron Lett. 2008, 49, 672) the product from the proline-catalyzed enantioselective aldol of 15 and 16, leading to the substituted piperidine 17 . Michael Shipman of the University of Warwick described (Tetrahedron Lett. 2008, 49, 250) the cyclization of the aziridine derived from 18, that proceeded to give 19 as a single diastereomer, apparently via kinetic side-chain protonation. Takeo Kawabata of Kyoto University found (J. Am. Chem. Soc. 2008, 130, 4153) that intramolecular alkylation to form four, five and six-membered rings from amino esters such as 21 proceeded with remarkable enantioretention. Géraldine Masson and Jieping Zhu of CNRS, Gif-sur-Yvette, condensed (Organic Lett. 2008, 10, 1509) cinnamaldehyde 23 with cyanide and an ω-alkenyl amine to give the intramolecular aza-Diels-Alder substrate 24. Hongbin Zhai of the Shanghai Institute of Organic Chemistry acylated (J. Org. Chem. 2008, 73, 3589) 26 with 27, leading to the ring-closing metathesis precursor 28.