Dong Zhang

Why would a politically centralized state embark on the path of economic decentralization? This Element delves into the political origin of the puzzling economic decentralization in mainland China. The authors contend that the intra-elite conflicts between the authoritarian ruler and the ruling elites within the state prompted the ruler to pursue decentralization as a strategy to curb the influence wielded by the ruling elites. By examining the composition of the Chinese Communist Party's Central Committee, they find that the Cultural Revolution, fueled by elite conflicts, shifted the elite selectorate's composition from favoring central agencies to favoring local interests. Subsequent low turnover reinforced this shift, aligning elite incentives with decentralization policies and committing the Chinese leadership to a decentralized path in the 1980s. Additionally, Taiwan's economic liberalization under the Kuomintang's authoritarian rule provides further evidence of the link between ruling party elite composition and economic policy orientation.

Why would a politically centralized state embark on the path of economic decentralization? This Element delves into the political origin of the puzzling economic decentralization in mainland China. The authors contend that the intra-elite conflicts between the authoritarian ruler and the ruling elites within the state prompted the ruler to pursue decentralization as a strategy to curb the influence wielded by the ruling elites. By examining the composition of the Chinese Communist Party's Central Committee, they find that the Cultural Revolution, fueled by elite conflicts, shifted the elite selectorate's composition from favoring central agencies to favoring local interests. Subsequent low turnover reinforced this shift, aligning elite incentives with decentralization policies and committing the Chinese leadership to a decentralized path in the 1980s. Additionally, Taiwan's economic liberalization under the Kuomintang's authoritarian rule provides further evidence of the link between ruling party elite composition and economic policy orientation.

Addressing the active and challenging field of spectral theory, this book develops the general theory of spectra of discrete structures, on graphs, simplicial complexes, and hypergraphs. In fact, hypergraphs have long been neglected in mathematical research, but due to the discovery of Laplace operators that can probe their structure, and their manifold applications from chemical reaction networks to social interactions, they now constitute one of the hottest topics of interdisciplinary research. The authors' analysis of spectra of discrete structures embeds intuitive and easily visualized examples, which are often quite subtle, within a general mathematical framework. They highlight novel research on Cheeger type inequalities which connect spectral estimates with the geometry, more precisely the cohesion, of the underlying structure. Establishing mathematical foundations and demonstrating applications, this book will be of interest to graduate students and researchers in mathematics working on the spectral theory of operators on discrete structures.

In den letzten zwei Jahrzehnten wurde die Landschaft der elektromechanischen Energieumwandlung durch zwei zusammenwirkende Kr fte grundlegend ver ndert: das explosive Wachstum von Halbleitern mit gro er Bandl cke und die stetig steigenden Anforderungen an h here Leistungsdichte, Fehlertoleranz und dynamisches Verhalten in sicherheitskritischen Antrieben. Diese Kr fte haben das dreiphasige Paradigma an seine thermischen, magnetischen und regelungstechnischen Grenzen gebracht und mehrphasige Permanentmagnetmaschinen von einer akademischen Kuriosit t zu einer etablierten Technologie in der elektrischen Flugzeugantriebstechnik, integrierten Bordnetzen von Schiffen, hybriden Schwerlastantrieben, Hochgeschwindigkeitskompressoranlagen und Windkraftanlagen der n chsten Generation gemacht. Unter den vielen mehrphasigen Systemen hat sich die duale Dreiphasen- (oder asymmetrische Sechsphasen-) Permanentmagnet-Synchronmaschine als die am schnellsten verbreitete Topologie erwiesen, da sie die Anzahl der Regelungsfreiheitsgrade elegant verdoppelt und gleichzeitig die bew hrten Fertigungsprozesse konventioneller Dreiphasenstatoren nutzt.

Nas ltimas duas d cadas, o panorama da convers o eletromec nica de energia foi silenciosamente reescrito por duas for as convergentes: o crescimento explosivo dos semicondutores de banda larga e a procura incessante de maior densidade de pot ncia, toler ncia a falhas e resposta transit ria em acionamentos cr ticos para a seguran a. Estas for as levaram o paradigma trif sico aos seus limites t rmicos, magn ticos e de controlo, e catapultaram as m quinas multif sicas de man permanente da curiosidade acad mica para o hardware convencional em propuls o el trica de aeronaves, sistemas de energia integrados a bordo de navios, tra o h brida para servi o pesado, comboios de compressores de alta velocidade e turbinas e licas de ltima gera o. Entre os muitos candidatos multif sicos, a m quina s ncrona de man permanente trif sica dupla (ou hexaf sica assim trica) emergiu como a topologia de ado o mais r pida, uma vez que duplica elegantemente o n mero de graus de liberdade de controlo, ao mesmo tempo que herda a cadeia de ferramentas de fabrico consolidada dos estatores trif sicos convencionais.

W ciągu ostatnich dw ch dekad krajobraz konwersji energii elektromechanicznej ulegl cichej, ale gruntownej transformacji pod wplywem dw ch zbieżnych sil gwaltownego rozwoju p lprzewodnik w szerokopasmowych oraz nieustannego zapotrzebowania na wyższą gęstośc mocy, odpornośc na awarie i szybką reakcję w napędach o krytycznym znaczeniu dla bezpieczeństwa. Sily te doprowadzily paradygmat tr jfazowy do granic jego możliwości termicznych, magnetycznych i sterowania, a wielofazowe maszyny z magnesami trwalymi przeksztalcily się z akademickiej ciekawostki w powszechnie stosowane rozwiązania w napędach elektrycznych samolot w, zintegrowanych systemach zasilania statk w, hybrydowych pojazdach ciężarowych, szybkich sprężarkach i turbinach wiatrowych nowej generacji. Spośr d wielu wielofazowych rozwiązań, dwufazowa (lub asymetryczna sześcioprzewodowa) synchroniczna maszyna z magnesami trwalymi stala się najszybciej adaptowaną topologią, ponieważ elegancko podwaja liczbę stopni swobody sterowania, jednocześnie wykorzystując dojrzale technologie produkcyjne konwencjonalnych tr jfazowych stojan w.

Negli ultimi due decenni, il panorama della conversione di energia elettromeccanica stato silenziosamente rivoluzionato da due forze convergenti: la crescita esplosiva dei semiconduttori a banda larga e l'incessante richiesta di maggiore densit di potenza, tolleranza ai guasti e risposta transitoria nei sistemi di azionamento critici per la sicurezza. Queste forze hanno spinto il paradigma trifase ai suoi limiti termici, magnetici e di controllo, e hanno trasformato le macchine a magneti permanenti multifase da semplice curiosit accademica a componenti hardware di uso comune nella propulsione di aeromobili elettrici, nei sistemi di alimentazione integrati a bordo delle navi, nella trazione ibrida per veicoli pesanti, nei compressori ad alta velocit e nelle turbine eoliche di nuova generazione. Tra le numerose configurazioni multifase, la macchina sincrona a magneti permanenti a doppia trifase (o esafase asimmetrica) si affermata come la topologia pi rapidamente adottata perch raddoppia elegantemente il numero di gradi di libert di controllo, pur ereditando la consolidata catena di produzione degli statori trifase convenzionali.

Au cours des deux derni res d cennies, le paysage de la conversion d' nergie lectrom canique a t profond ment transform par deux forces convergentes: la croissance exponentielle des semi-conducteurs large bande interdite et la demande incessante de densit de puissance, de tol rance aux d fauts et de r ponse transitoire accrues dans les syst mes d'entra nement critiques pour la s curit . Ces forces ont pouss le paradigme triphas ses limites thermiques, magn tiques et de contr le, et ont propuls les machines multiphas es aimants permanents du statut de curiosit acad mique celui de composant standard dans la propulsion des avions lectriques, les syst mes d'alimentation int gr s bord des navires, la traction hybride pour v hicules lourds, les compresseurs grande vitesse et les oliennes de nouvelle g n ration. Parmi les nombreuses architectures multiphas es, la machine synchrone aimants permanents double triphas e (ou six phases asym triques) s'est impos e comme la topologie la plus rapidement adopt e, car elle double l gamment le nombre de degr s de libert de contr le tout en b n ficiant des proc d s de fabrication prouv s des stators triphas s conventionnels.