The Seasonal Adjustment Procedures for the Consumer Price Indexes: Some Empirical Results

Beginning with January of 1987, the consumer price indexes (CPI's) have been seasonally adjusted by the X-11 autoregressive integrated moving average (ARIMA) procedure. This modification of the X-11 procedure was introduced following an empirical investigation into three aspects of seasonal adjustment methodology as applied to several CPI series—the choice of ARIMA models to fit and forecast those series, the improvements made by the ARIMA modification in terms of revision and smoothness of the seasonally adjusted series, and the effect on the quality of seasonal adjustment and the identifiability of seasonality due to the ARIMA modification. This article reports the results of that investigation, in addition, a brief account is given of the U.S. Bureau of Labor Statistics procedures relating to the projected seasonal factors, seasonally adjusted aggregate series, and the revisions of the seasonally adjusted series.     

Interaction Between Concurrent Transactions in the Design of Distributed Databases

A distributed database system allows concurrent execution of transactions from multiple users at multiple locations. This paper presents a general scheme of including the effect of interaction between such transactions in the design process of distributed databases. This scheme allows the decision maker to choose the most appropriate design for a distributed database. The interaction effect is a consequence of concurrency control procedures and contention for system resources. Prior research has not included all components of the interaction effect in the design process. A separate module, called an interaction module, was built to measure the interaction effect using a comprehensive simulation model of a general purpose relational distributed database management system (DBMS). The interaction module can be interfaced with any distributed database design system as an add-on module so that the interaction effect can be included in the design process. A detailed example demonstrates the use of the interaction module in the decision-making process. Experiments conducted using the module show that the interaction effect can be significant and that it can affect the choice of the design. Experiments were also conducted to measure the sensitivity of design choices under changing input conditions.     

Projecting populations for major Pacific Island countries with and without COVID-19: pro-active insights for population policy

Journal of Population Research - The paper projects aggregate populations of six Pacific Island countries in both pre- and post-COVID19 scenarios using a Cohort Component Method for the period...     

A Heuristic Algorithm for the Capacitated Multiple Supplier Inventory Grouping Problem

This paper presents and solves a model for the multiple supplier inventory grouping problem, which involves the minimization of logistics costs for a firm that has multiple suppliers with capacity limitations. The costs included in the model are purchasing, transportation, ordering, and inventory holding, while the firm's objective is to determine the optimal flows and groups of commodities from each supplier. We present an algorithm, which combines subgradient optimization and a primal heuristic, to quickly solve the multiple supplier inventory grouping problem. Our algorithm is tested extensively on problems of various sizes and structures, and its performance is compared to that of OSL, a state-of-the-art integer programming code. The computational results indicate that our approach is extremely efficient for solving the multiple supplier inventory grouping problem.