## The V -I characteristic of a photocell can be described by a rather complex mathematical formula

The V -I characteristic of a photocell can be described by a rather complex mathematical formula, which can be handled with a computer but is too complicated for an in-class exam. To simplify handling, we are adopting, rather arbitrarily, a simplified characteristic consisting of two straight lines as shown in the above. The position of point C, of maximum output, varies with the Iν/I0 ratio. Empirically, VC = VOC 0.7+0.0082 ln Iν I0 and IC = Iν 0.824 + 0.0065 ln Iν I0 . Now consider silicon photodiodes operating at 298 K. These diodes form a panel, 1 m2 in area, situated in Palo Alto (latitude 37.4◦ N, longitude 125◦ W). The panel faces true south and has an elevation of 35◦. In practice, the panel would consist of many diodes in a series/parallel connection. In the here, assume that the panel has a single enormous photodiode. Calculate the insolation on the surface at a 1130 PST and at 1600 PST on October 27. Assume clear meteorological conditions. Assume that the true solar time is equal to the PST. 1. Calculate the insolation on the collector at the two moments mentioned.

## Let s be an object model schedule with terminated subtransactions. The expansion

Let s be an object model schedule with terminated subtransactions. The expansion of s, denoted exp(s), is an object model history that is derived from s in the following way: 1. All operations whose parent has a commit child are included in exp(s). 2. For each operation whose parent p~ has an abort child a~v, an inverse operation for each of p's v – ] forward operations is added, provided the forward operations themselves have a commit child, the abort child of p is removed, and a child c~(2v-1) is added to p. The inverse operations have the reverse order of the corresponding forward operations and follow all forward operations; the Commit operation follows all other children of p. All new children of p precede an operation q in exp(s) if the abort child of p preceded q in s. 3. For each transaction in active(s), inverse operations and a final commit child are added as children of the corresponding transaction root, with their ordering defined analogously to the above case of an aborted subtransaction.

## An object model schedule s is called extended tree reducible if its expansion

An object model schedule s is called extended tree reducible if its expansion, e• can be transformed into a serial order of s's committed transaction roots by applying the following transformation rules finitely many times: 1. the commutativity rule applied to adjacent leaves, i.e., two adjacent leaves that are not in conflict can be commuted; 2. the tree pruning rule for isolated subtrees, i.e., if all Li operations of a transaction are isolated, then its Li-1 operations can be eliminated; 3. the undo rule applied to adjacent leaves, i.e., two adjacent leaf operations p and p-1 that are inverses of each other can be replaced by a null operation; 4. the null rule for read-only operations; 5. the ordering rule applied to unordered leaves. Let FRED denote the class of all extended tree-reducible object model schedules.

## A layered object model schedule s (with perfect commutativity tables

A layered object model schedule s (with perfect commutativity tables at all levels) is extended tree reducible, i.e., in class ETRED, if all its level-to-level schedules are conflict serializable and strict and s is conflict faithful.

A layered object model schedule s (with perfect commutativity tables at all levels)is in ETRED if all its level-to-level schedules are order preserving conflict serializable and strict.

## What are the short-circuit currents (Iν) under the two illuminations

What are the short-circuit currents (Iν) under the two illuminations? Consider the sun as a 6000-K black body.

Suppose that at 1600 the load resistance used was the same as that which optimized the 1130 output. What are the power in the load and the efficiency?

## The layered S2PL protocol generates only schedules in ETRED. Let sl = wl (x)wl (y)r2 (u)w2 (x)r2 (y)w2 (y)a2wl (z)cl and s2 = wl (x)wl (y)r2 (u)w2 (x)r2 (y)w2 (y)wl (z)al c2 Determine exp(sl) and exp(s2) as well as the corresponding reductions. The key point of a page sequence number is that it can give us some partial knowledge about the order of the write actions (including full-write actions) that have been performed on it.

The layered S2PL protocol generates only schedules in ETRED. Let sl = wl (x)wl (y)r2 (u)w2 (x)r2 (y)w2 (y)a2wl (z)cl and s2 = wl (x)wl (y)r2 (u)w2 (x)r2 (y)w2 (y)wl (z)al c2 Determine exp(sl) and exp(s2) as well as the corresponding reductions.

The key point of a page sequence number is that it can give us some partial knowledge about the order of the write actions (including full-write actions) that have been performed on it.

## When exposed to the higher of the two insolations, the opencircuit voltage of the photodiode

When exposed to the higher of the two insolations, the opencircuit voltage of the photodiode is 0.44 V. What is the power delivered to a load at 1130 and at 1600? The resistance of the load is, in each case, that which maximizes the power output for that case. What are the load resistances? What are the efficiencies?

## Which of the properties RC, ST, RG, PRED, and LRC are satisfied by the following schedules

Which of the properties RC, ST, RG, PRED, and LRC are satisfied by the following schedules: Sl = rl (a)r2 (a)wl (a)cl c2 s2 = rl (a)wl (a)r2 (b)w2 (b)w2 (a)czcl s3 = rl (a)incr2 (a)incr2 (b)incr3 (b)c3azcl Some of the above properties cannot be applied to a schedule with operations other than read and write, such as schedule s3 above. Try to define generalizations of these properties to flat object schedules with arbitrary operations.

## Prove Theorem 11.6 stating that Gen(SS2PL) = RG. THEOREM 11.6 Strong two-phase locking

Prove Theorem 11.6 stating that Gen(SS2PL) = RG. THEOREM 11.6 Strong two-phase locking (SS2PL) generates exactly the class of rigorous schedules, i.e., Gen(SS2PL) = RG. SS2PL produces exactly RG The proof is left as an (see 11.7). If we relax SS2PL to S2PL, we arrive at the following result (which can serve as a justification for the name “strict 2PL”).

## An EV experiences an aerodynamic drag of 320 N when operated at sea level

An EV experiences an aerodynamic drag of 320 N when operated at sea level (1 atmosphere) and 30 C. What is the drag when operated at the same speed at La Paz, Bolivia (4000-m altitude, air pressure 0.6 atmospheres) and at a temperature of −15 C?