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A simple and computationally efficient scheme for tree-structured vector quantization is presented. Unlike previous methods, its quantization error depends only on the intrinsic dimension of the data distribution, rather than the apparent dimension of the space in which the data happen to lie.

A service system is an organization of the resources and processes, which interacts with the customer and produces service outcomes. Since a majority of the service systems are labor-intensive, the main resources are the service workers. Designing such service systems is nontrivial due to a large number of parameters and variations, but crucial for business decisions such as labor staffing. The most important design point of a service system is how and when service requests are assigned to service workers a.k.a. dispatching policy. This paper presents a framework for evaluation of dispatching policies in service systems. A discrete event simulation model of a service system in the data-center management domain is presented. We evaluate four dispatching policies on five real-life service systems. We observe that the simulation-based approach incorporates intricacies of service systems and allows comparative analysis of dispatching policies leading to more accurate decisions on labor staffing. INTRODUCTIONService-based economies and business models have gained significant importance. The clients and service providers exchange value through service interactions and reach service outcomes. Given the focus on the individual customer's value and the uniqueness of the customer's needs, the service providers need to meet a large variety of expectations set by the customers. This is the primary reason for the service delivery to be labor-intensive where human intervention and interaction is unavoidable. Service providers aim to maintain the quality, even in the face of unique customer expectations, by structuring their service delivery operations as service systems (SS). A SS is an organization of the resources that support and the processes that drive service interactions so that the outcomes meet customer expectations (Alter 2008;Spohrer et al. 2007;Ramaswamy and Banavar 2008). This paper focuses on the SS in the data-center management domain. However, the contributions of this paper extend to all laborintensive SS.In the domain of data-center management, the customers own data centers and other IT infrastructures supporting their business. The size, complexity, and uniqueness of the technology installations drive outsourcing of the management responsibilities to specialized service providers. The service providers manage the data-centers from remote locations called delivery centers where groups of service workers (SW) skilled in specific technology areas support corresponding service requests (SR). In each group, the processes, the people, and the customers that drive the operations of a delivery center constitute a SS. A delivery center is a system of multiple SS. This paper focuses on the problem of designing the process of routing the SRs to the right technicians (a.k.a. dispatching policy) within a SS such that certain objectives are achieved and constraints are met. What is the basis for evaluating dispatching policies? We propose that the best dispatching policy is the one that: (1) satisfies the contractual con...

A suite of high‐Mg–Al granulites from Sunkarametta, Eastern Ghats Belt, India, shows contrasting prograde assemblages of extremely aluminous orthopyroxene+cordierite+sapphirine and similarly aluminous orthopyroxene+Ti‐rich spinel in closely associated domains. Textural and compositional characteristics indicate that both were derived from prograde dehydration–melting of biotite–plagioclase–quartz‐bearing protoliths. The former assemblage was stabilized at relatively more magnesian bulk composition. Geothermobarometric data and petrogenetic grid considerations place ‘peak’ metamorphic conditions at c. 950 °C and 9 kbar. Subsequent to peak metamorphism, the rocks cooled to c. 700–750 °C, with slight lowering of pressure, and the retrograde reactions also involved melt–solid interaction. The inferred P–T  trajectory is one of heating–cooling at lower crustal (25–30 km) depths.

A suite of metapelitic, basic and quartzofeldspathic rocks intruded by enderbitic gneiss from the southernmost tip of the Eastern Ghats Belt, India, and metamorphosed at c. 750–800 °C, 6 kbar, were subjected to repeated ductile shear deformation, hydration, cooling and accompanying alkali metasomatism along narrow shear zones. Gedrite‐bearing assemblages developed in the shear zones traversing metapelitic rocks. Interpretation of the reaction textures in an appropriate P–T  grid in the system FMASH, an isothermal–isobaric μH2O–μNa2O grid in the system NFMASH, and geothermobarometric data suggest a complex evolutionary history for the gedrite‐bearing parageneses. Initially, gedrite‐bearing assemblages were produced due to increase in μNa2O at nearly constant but high μH2O accompanying cooling. Gedrite was partially destabilized to orthopyroxene+albite due to progressively increasing μNa2O. During further cooling and at increased μH2O a second generation of gedrite appeared in the rocks.