1. A system providing levelness of a production schedule, comprising:
a database that stores demand data of one or more items to be processed within a sequence of tasks; and
a computer coupled with the database and configured to:
access the demand data of the one or more items;
calculate one or more time intervals for each of the one or more items;
calculate a weighted average for each of the one or more items;
calculate a time ratio according to the sequence of tasks by:
calculating the average of the calculated time intervals and the calculated weighted averages; and
calculating a minimum ratio of an adjusted time interval for each of the one or more items and the calculated weighted averages, upper bounded by unity;
generate a production schedule based on a sequence of tasks having a predetermined calculated time ratio; and
store the generated production schedule in the database.
2. The system of claim 1, wherein the computer is further configured to:
determine a total number of tasks within the sequence of tasks and a total number of tasks for each of the one or more items based on the accessed demand data of the one or more items.
3. The system of claim 2, wherein the one or more time intervals is determined by calculating the ratio of the total number of tasks within the sequence of tasks and the total number of tasks for each of the one or more items.
4. The system of claim 1, wherein the computer is further configured to:
determine a number of subsequences of tasks within the sequence of tasks for each of the one or more items which have at least TA tasks, where TA is the largest whole number smaller than or equal to the time interval of the item.
5. The system of claim 4, wherein the computer is further configured to:
for each of the subsequence of tasks within the sequence of tasks calculate a weight of each of the one or more items based on:
1+|TA\u2212X|
wherein TA is representative of the time interval for each of the one or more items and X is representative of the number of tasks within the subsequence of tasks.
6. The system of claim 5, wherein the computer is further configured to:
calculate a weighted average for each of the one or more items in accordance with the determined number of tasks within the subsequence of tasks and the calculated weight of each of the one or more items.
7. The system of claim 1, wherein the computer is further configured to determine a new order of tasks within the sequence of tasks.
8. A computer-implemented method of providing levelness of a production schedule, comprising:
accessing, by a computer, demand data of one or more items to be processed within a sequence of tasks;
calculating, by the computer, one or more time intervals for each of the one or more items;
calculating, by the computer, a weighted average for each of the one or more items;
calculating, by the computer, a time ratio according to the sequence of tasks by:
calculating the average of the calculated time intervals and the calculated weighted averages; and
calculating a minimum ratio of an adjusted time interval for each of the one or more items and the calculated weighted averages, upper bounded by unity;
generating, by the computer, a production schedule based on a sequence of tasks having a predetermined calculated time ratio; and
storing, by the computer, the generated production schedule in the database.
9. The method of claim 8, further comprising:
determining a total number of tasks within the sequence of tasks and a total number of tasks for each of the one or more items based on the accessed demand data of the one or more items.
10. The method of claim 9, wherein the one or more time intervals is determined by calculating the ratio of the total number of tasks within the sequence of tasks and the total number of tasks for each of the one or more items.
11. The method of claim 8, further comprising:
determining a number of subsequences of tasks within the sequence of tasks for each of the one or more items which have at least TA tasks, where TA is the largest whole number smaller than or equal to the time interval of the item.
12. The method of claim 11, further comprising:
for each of the subsequences of tasks within the sequence of tasks calculating a weight of each of the one or more items based on:
1+|TA\u2212X|
wherein TA is representative of the time interval for each of the one or more items and X is representative of the number of tasks within the subsequence of tasks.
13. The method of claim 12, further comprising:
calculating a weighted average for each of the one or more items in accordance with the determined number of tasks within the subsequence of tasks and the calculated weight of each of the one or more items.
14. The method of claim 8, further comprising:
determining a new order of tasks within the sequence of tasks.
15. A computer-readable medium embodied with software providing levelness of a production schedule, the software when executed using one or more computers is configured to:
access demand data of one or more items to be processed within a sequence of tasks;
calculate one or more time intervals for each of the one or more items;
calculate a weighted average for each of the one or more items;
calculate a time ratio according to the sequence of tasks by:
calculating the average of the calculated time intervals and the calculated weighted averages; and
calculating a minimum ratio of an adjusted time interval for each of the one or more items and the calculated weighted averages, upper bounded by unity;
generate a production schedule based on a sequence of tasks having a predetermined calculated time ratio; and
store the generated production schedule in the database.
16. The computer-readable medium of claim 15, wherein the software is further configured to:
determine a total number of tasks within the sequence of tasks and a total number of tasks for each of the one or more items based on the accessed demand data of the one or more items.
17. The computer-readable medium of claim 16, wherein the one or more time intervals is determined by calculating the ratio of the total number of tasks within the sequence of tasks and the total number of tasks for each of the one or more items.
18. The computer-readable medium of claim 15, wherein the software is further configured to:
determine a number of subsequences of tasks within the sequence of tasks for each of the one or more items which have at least TA tasks, where TA is the largest whole number smaller than or equal to the time interval of the item.
19. The computer-readable medium of claim 18, wherein the software is further configured to:
for each of the subsequence of tasks within the sequence of tasks calculate a weight of each of the one or more items based on:
1+|TA\u2212X|
wherein TA is representative of the time interval for each of the one or more items and X is representative of the number of tasks within the subsequence of tasks.
20. The computer-readable medium of claim 19, wherein the software is further configured to:
calculate a weighted average for each of the one or more items in accordance with the determined number of tasks within the subsequence of tasks and the calculated weight of each of the one or more items.
21. The computer-readable medium of claim 15, wherein the software is further configured to:
determine a new order of tasks within the sequence of tasks.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An optical disk substrate, comprising:
an annular substrate, having a supporting portion and a recording portion surrounding the supporting portion, the recording portion having a recording surface; and
a protruding portion overlaid on the supporting portion, the protruding portion having a supporting surface which is on a different plane from the recording surface and having a plurality of indentations on its outer periphery,
wherein the total thickness of the protruding portion and the supporting portion is greater than the thickness of the recording portion.
2. The optical disk substrate as described in claim 1, wherein the outermost periphery of the protruding portion is inclined outwards from the plane on which the supporting surface is located to the plane on which the recording surface is located.
3. The optical disk substrate as described in claim 1, wherein the total thickness of the protruding portion and the supporting portion is between 0.66 mm and 1.6 mm.
4. The optical disk substrate as described in claim 1, wherein the thickness of the recording portion is between 0.55 mm and 0.65 mm.
5. The optical disk substrate as described in claim 1, wherein the diameter of the annular substrate is between 70 mm and 90 mm.
6. The optical disk substrate as described in claim 1, wherein the diameter of the annular substrate is between 110 mm and 130 mm.
7. The optical disk substrate as described in claim 1, wherein the supporting surface and the recording surface are on the same side of the annular substrate.
8. The optical disk substrate as described in claim 1, wherein the supporting surface and the recording surface are on different sides of the annular substrate.
9. The optical disk substrate as described in claim 1, wherein the annular substrate and the protruding portion are molded in one piece.
10. The optical disk substrate as described in claim 1, wherein the annular substrate and the protruding portion are assembled.
11. An optical disk, comprising:
an optical disk substrate, which comprises:
an annular substrate, having a supporting portion and a recording portion surrounding the supporting portion, the recording portion having a recording surface; and
a protruding portion overlaid on the supporting portion, the protruding portion having a supporting surface which is on a plane different from the recording surface and having a plurality of indentations on its outer periphery,
wherein the total thickness of the protruding portion and the supporting portion is greater than the thickness of the recording portion; and
a paint layer formed on the recording surface for recording data.
12. The optical disk as described in claim 11, wherein the outermost periphery of the protruding portion is inclined outwards from the plane on which the supporting surface is located to the plane on which the recording surface is located.
13. The optical disk as described in claim 11, further comprising:
a compensation sheet overlaid on the paint layer.
14. The optical disk as described in claim 11, wherein the total thickness of the protruding portion and the supporting portion is between 0.66 mm and 1.6 mm.
15. The optical disk as described in claim 11, wherein the thickness of the recording portion is between 0.55 mm and 0.65 mm.
16. The optical disk as described in claim 11, wherein the diameter of the annular substrate is between 70 mm and 90 mm.
17. The optical disk as described in claim 11, wherein the diameter of the annular substrate is between 110 mm and 130 mm.
18. The optical disk as described in claim 11, wherein the supporting surface and the recording surface are on the same side of the annular substrate.
19. The optical disk as described in claim 11, wherein the supporting surface and the recording surface are on different sides of the annular substrate.
20. The optical disk as described in claim 11, wherein the annular substrate and the protruding portion are molded in one piece.
21. The optical disk as described in claim 11, wherein the annular substrate and the protruding portion are assembled.
22. The optical disk as described in claim 11, wherein the paint layer comprises:
at least one recording layer located on the recording surface;
a reflection layer located on the recording layer; and
a protection layer located on the reflection layer.
23. The optical disk as described in claim 22, wherein the recording layer is composed of dyes and the reflection layer is composed of metal.
24. The optical disk as described in claim 11, wherein the paint layer comprises:
a first dielectric layer located on the recording surface;
a recording layer located on the first dielectric layer;
a second dielectric layer located on the recording layer;
an insulation layer located on the second dielectric layer;
a reflection layer located on the insulation layer; and
a protection layer located on the reflection layer.
25. The optical disk as described in claim 24, wherein:
the recording layer is composed of alloy, an upper separation layer of the alloy, and a lower separation layer of the alloy; and
the reflection layer is composed of metal.