Assigning readers to cases in imaging studies using balanced incomplete block designs

In many imaging studies, each case is reviewed by human readers and characterized according to one or more features. Often, the inter-reader agreement of the feature indications is of interest in addition to their diagnostic accuracy or association with clinical outcomes. Complete designs in which all participating readers review all cases maximize efficiency and guarantee estimability of agreement metrics for all pairs of readers but often involve a heavy reading burden. Assigning readers to cases using balanced incomplete block designs substantially reduces reading burden by having each reader review only a subset of cases, while still maintaining estimability of inter-reader agreement for all pairs of readers. Methodology for data analysis and power and sample size calculations under balanced incomplete block designs is presented and applied to simulation studies and an actual example. Simulation studies results suggest that such designs may reduce reading burdens by >40% while in most scenarios incurring a <20% increase in the standard errors and a <8% and <20% reduction in power to detect between-modality differences in diagnostic accuracy and [Formula: see text] statistics, respectively.

A Construction Technique for Group Divisible (v-1,k,0,1) Partially Balanced Incomplete Block Designs (PBIBDs)

Group Divisible PBIBDs are important combinatorial structures with diverse applications. In this paper, we provided a construction technique for Group Divisible (v-1,k,0,1) PBIBDs. This was achieved by using techniques described in literature to construct Nim addition tables of order 2n, 2≤n≤5 and (k2,b,r,k,1)Resolvable BIBDs respectively. A “block cutting” procedure was thereafter used to generate corresponding Group Divisible (v-1,k,0,1) PBIBDs from the (k2,b,r,k,1)Resolvable BIBDs. These procedures were streamlined and implemented in MATLAB. The generated designs are regular with parameters(15,15,4,4,5,3,0,1);(63,63,8,8,9,7,0,1);(255,255,16,16,17,15,0,1) and (1023,1023,32,32,33,31,0,1). The MATLAB codes written are useful for generating the blocks of the designs which can be easily adapted and utilized in other relevant studies. Also, we have been able to establish a link between the game of Nim and Group Divisible (v-1,k,0,1) PBIBDs.

Construction of Complete Diallel Crosses Plans

In this paper Complete Diallel Crosses (CDC) plan is constructed using two Balanced Incomplete Block Designs and the Galois field with the same set of parametersI. The designs were isomorphic on each other and the crossing is made between the lines. The analysis of CDC plans to estimate the general combining ability (GCA) effects and specific combining ability (SCA) effects were excluded from the model. The efficiency value of the constructed CDC plan is tends to 1, and universally optimum when v is very large. The construction is also illustrated with the suitable example.

Pairwise Balanced Designs From Cyclic PBIB Designs

A pairwise balanced designs was constructed using cyclic partially balanced incomplete block designs with either (λ1 – λ2) = 1 or (λ2 – λ1) = 1. This method of construction of Pairwise balanced designs is further generalized to construct it using cyclic partially balanced incomplete block design when |(λ1 – λ2)| = p. The methods of construction of pairwise balanced designs was supported with examples. A table consisting parameters of Cyclic PBIB designs and its corresponding constructed pairwise balanced design is also included.

A SIMPLE GENERALIZED CONSTRUCTION OF RESOLVABLE BALANCED INCOMPLETE BLOCK DESIGNS WITH PRIME BLOCK SIZES

This paper presents a Simple Generalized Construction of Resolvable Balanced Incomplete Block Designs whose parameter combination is of the form $v=k^2, ~r=k+1, ~\lambda=k^0=1$, where $k$ is prime. The design construction was achieved by using the cyclic subgroup of the symmetric group $S_k$ whose generator is one of the permutations of the $2$-permutation generating set of the Dihedral group $D_k$ and $2$-permutation generating set of the presentation of $S_k$. The method is efficient, sufficient and also mitigate against the tediousness encountered in other methods of construction when $v$ is large.

Nested block design as key pre-distribution in wireless sensor networks

An accumulation of wireless sensor nodes is combined together to form the Wireless Sensor Networks. The sensor nodes are distributed haphazardly without any decided method into a natural setting, which is generally inhospitable and it is difficult to provide key-chains to each node for security as they are haphazardly distributed. In this paper, we use Nested Block Design (NBD) as Key Pre-distribution Scheme (KPS) and found out that NBD support large networks with fewer keys in each node than Symmetric Balanced Incomplete Block Designs (SBIBD) and Transversal Design (TD[Formula: see text]), provide higher resiliency than SBIBDs and better connectivity than TD[Formula: see text], tradeoff between local connectivity and resiliency ([Formula: see text]) is lower than SBIBD but more than TD[Formula: see text] and key-node ratio ([Formula: see text]) is same for [Formula: see text] but lower than SBIBD.