The situation of simultaneous satisfaction of row minima and column minima rule is termed as
Understanding key terms in optimization problems like the transportation problem is crucial. The question asks about a specific situation that arises when allocating resources, related to satisfying both row and column conditions simultaneously. Let's break down the concepts involved.
In a transportation problem, the goal is often to find the minimum cost to transport goods from sources (rows) to destinations (columns), satisfying supply at sources and demand at destinations. When finding an initial basic feasible solution (IBFS) using methods like the Least Cost Method or Vogel's Approximation Method, we allocate units to cells.
A basic feasible solution in a transportation problem should ideally have exactly \(m + n - 1\) occupied cells (allocations), where \(m\) is the number of rows (sources) and \(n\) is the number of columns (destinations). This condition ensures that the solution is non-degenerate and can be easily tested for optimality using methods like the Stepping Stone Method or MODI Method.
Degeneracy occurs when the number of occupied cells in a basic feasible solution is less than \(m + n - 1\). This situation causes difficulties when trying to find closed loops for optimality testing, as required cells might be unoccupied.
The phrase "simultaneous satisfaction of row minima and column minima rule" likely refers to a scenario during the allocation process in methods like the Least Cost Method or Vogel's Approximation Method. In these methods, you select a cell (often based on minimum cost or penalty) and allocate the minimum of the available supply in the row and the required demand in the column. If, during an allocation step, the amount allocated is exactly equal to both the remaining supply of the row and the remaining demand of the column, then both the row and the column are simultaneously satisfied (their remaining supply/demand becomes zero). This simultaneous satisfaction means you have 'used up' both a row constraint and a column constraint with a single allocation.
Normally, an allocation would exhaust either a row or a column, leading to the satisfaction of one constraint. Exhausting both simultaneously means you are, in a sense, satisfying two constraints with one allocation step where you might otherwise expect two separate steps or one step followed by another for the remaining non-zero supply/demand.
Consider an allocation \(x_{ij}\) to cell (i, j) where the available supply in row i is \(a_i\) and the required demand in column j is \(b_j\). The allocation is \(x_{ij} = \min(a_i, b_j)\). If \(a_i = b_j\), then \(x_{ij} = a_i = b_j\). This single allocation satisfies both the i-th row's supply and the j-th column's demand. When this happens, and assuming this is not the very last allocation, this specific step contributes only one occupied cell towards the total count, whereas exhausting just a row or just a column would typically leave the other dimension with a non-zero amount, potentially requiring a subsequent allocation step that would add another occupied cell.
This simultaneous reduction of both row supply and column demand to zero means that the number of allocations made to satisfy all constraints might end up being less than the expected \(m + n - 1\), leading directly to a degenerate basic feasible solution.
Let's look at the other options provided:
Based on the analysis, the situation where satisfying row and column conditions happens simultaneously during allocation, resulting in fewer than \(m+n-1\) occupied cells, is termed as Degeneracy.
| Term | Description in Transportation Problems |
|---|---|
| Degeneracy | Number of occupied cells in a basic feasible solution is < \(m + n - 1\). Often caused by simultaneous satisfaction of row and column constraints during allocation. |
| Unboundedness | Not applicable to standard transportation problems. |
| Infeasibility | No solution satisfies all constraints (e.g., total supply ≠ total demand in a balanced problem). |
| Post-optimality analysis | Analyzing the impact of parameter changes on the optimal solution after finding it. |
| Concept | Key Characteristic | Relevance to the Question |
|---|---|---|
| Basic Feasible Solution (BFS) | A solution satisfying supply/demand constraints with occupied cells. | The starting point where degeneracy is identified. |
| Number of occupied cells | Should be \(m + n - 1\) for a non-degenerate BFS. | Degeneracy occurs when this number is less than expected. |
| Allocation step | Assigning units to a source-destination cell. | Simultaneous satisfaction of row/column constraints during an allocation causes degeneracy. |
| Degeneracy | Fewer than \(m + n - 1\) occupied cells. | Directly answers the question posed. |
Degeneracy, while not preventing finding a solution, can make the standard optimality test methods (like Stepping Stone or MODI) difficult to apply directly because it might be impossible to form a closed loop for certain unoccupied cells. To handle degeneracy and proceed with optimality testing, a very small positive quantity, usually denoted by ε (epsilon), is introduced into one or more unoccupied cells that would allow the formation of loops. The ε value is treated like a basic variable but is considered to be zero in practice. This ε is placed in a cell such that it helps create \(m + n - 1\) basic variables (occupied cells + cells with ε). The standard optimality test can then be applied, treating cells with ε just like regular occupied cells in loop formation. After finding the optimal solution, ε is set back to zero.
Identify the correct combination of properties of point estimates form the options given below:
(a) Efficiency
(b) Consistency
(c) Adequacy
(d) Unbiasedness
Choose correct option:
In Operations management of an organization, the activities that assure the actual performance in accordance with planned performance are called:
Match the symbols used in preparation of process chart given in List - I with their description in List - II:
| List - I Symbols used in process chart | List - II Description |
|---|---|
| A. $\nabla$ | I. Movement from place to place |
| B. $\square$ | II. Delay |
| C. $\bigcirc$ | III. Inspection for quantity and quality |
D. ![]() | IV. Movement and Operation |
Choose the correct answer from the options given below :