PROPHASE 2. METAPHASE TELOPHASE 3. ANAPHASE

Chapter 1 • Introduction 33 The user clicks “Next” button to proceed the state indicator still shows “Metaphase”. The centromeres of each sister chromatid become attached by spindle fibers to opposite poles of the cell. The lines representing the spindle fibers should appear now, but they should be disabled, so the user cannot manipulate the chromosomes. The user clicks “Next” button to proceed into anaphase. Cell Nucleus Guidelines Beads Centromeres Step 0a: Build the parent cell Parent cell Next Step 0b: Interphase Step 1: Prophase Animation: The nucleus dissolves into the cell cytoplasm Next Next Next Spindle fibers Equatorial plane Step 2: Metaphase Next Next Figure 1-17: Simulation of the mechanics of cell division. continued below Ivan Marsic • Rutgers University 34 Step 3 Anaphase. The sister centromeres move to opposite poles and the attached chromatids are carried along, trailing out behind in a V-shape. The user should carry out the movement of the chromosomes by mouse manipulation. The spindle fibers become enabled to allow the user to manipulate chromosomes on screen. The user should click on a centromere and drag it towards the end of its spindle fiber. Only an outline is shown for the centromere that is interacted with. As a chromosome is pulled away by the user, it bends with the direction of movement. The chromosome opposite to it mirrors this action and moves in synchrony. A series of parabolas were used to model the changing shape of the chromosome as it is being pulled. See discussion below on how to draw the parabolas. Step 3: Anaphase Manipulated centromere Next Step 4: Telophase Animation: Nucleus condenses from the cytoplasm and the cell splits in two Next Figure 1-17: continued Simulation of the mechanics of cell division. Chapter 1 • Introduction 35 The user can release mouse button at any time and the chromosomes would freeze in the current position. The user can resume later from where they stopped, until the chromosomes are brought to the poles of the cell. The system should allow swinging the chromosome back and forth, not only in one direction towards the pole. The user clicks “Next” button after the chromosomes have been properly placed. Step 4 Telophase. In telophase, the spindle fibers disappear, the chromosomes start to de- condense not shown in the simulation, and two nuclear envelopes form. The user should click “Next” to watch the cell divide into two separate cells. Animation of the cell splitting and forming two nuclei is displayed. This concludes the process of mitosis. In anaphase Step 3 above, as a chromosome is pulled away by the user, it bends with the direction of movement. The chromosome opposite to it mirrors this action. A series of parabolas were used to model the changing shape of the chromosome as it is being pulled. Let us consider that the right chromosome is being manipulated dragged horizontally to the right. If x represents the amount of displacement in the horizontal axis, then the vertical displacement is represented by y, as in: x = −a ⋅ y 2 , where 0 ≤ a ≤ 1 P1-1 Initially, the shape of the chromosome is a straight line, so the curvature a = 0. When the chromosome is pulled all the way to the end of the spindle fiber, a = 1. As the user drags the centromere to the right, the line begins to curve, so the curvature of the parabola depends on the x-position of the centromere. In order for the animation to look correct, the individual beads must remain equidistant from each other on the curve as the curvature changes see Figure 1-18. In other words, if two adjacent beads are d b units apart when the chromosome is in its initial straight line position, when the chromosome reaches its final position, the distance on the curve, or the arclength between the two adjacent beads should remain d b units. To find the position of each of these beads, the arclength equation for P1-1 must be known in order to calculate the x and y positions of the beads. Chromosome Spindle Interaction point d b Displacement x d b a b S y Figure 1-18: Chromosome manipulation. a Initial shape. b Displaced along the spindle. Ivan Marsic • Rutgers University 36 The equation for the arclength of a function fy, which in our case is fy = −a ⋅ y 2 , equals: ∫ ∫ ∫ + ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ⋅ = ⋅ + = ⎟⎟ ⎠ ⎞ ⎜⎜ ⎝ ⎛ + = dy y a a dy y a dy dy y df S 2 2 2 2 2 2 1 2 4 1 1 From the table of integrals, we find that ∫ + + + ⋅ + + ⋅ = + C y b y b y b y dy y b 2 2 2 2 2 2 2 ln 2 2 and in our case b = 12a. Finally, we obtain: 2 2 2 2 2 1 ln 4 1 2 1 y a y a y a y a S + ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ + ⋅ + + ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ ⋅ ⋅ = P1-2 For every x-position the centromere is dragged along the spindle fiber, a corresponding parabolic shape is calculated. This calculation gives the parameter a. The parameter S, which is different for each bead, is the distance from the center of the centromere to the center of the particular bead along the line or curve. For each bead S should remain constant regardless of the amount of the chromosome bending. With these two values, the y-position of the particular bead can be calculated by using P1-2, and the corresponding x-position can be calculated by using P1-1. Domain Fieldwork Most of the fieldwork is already done, but the student can visit the local biology department and discuss with the instructors about possible enhancements and alterations to make it more suitable for their educational goals. It may be helpful to consult a cell biology textbook to gain better understanding of the cell division process. Technologies to Be Used Macromedia Flex should be used for programming, so that the virtual lab can be loaded in any browser that has Macromedia Flash plug-in. Another option is to use Java 2D and implement the lab as a Java Applet. Extensions By comparing Figure 1-16 and Figure 1-17, the reader will quickly notice that the basic simulation described above grossly oversimplifies the mitotic process. More ambitious students should consider adding more details to the simulation, perhaps in consultation with the biology department faculty. The above design does not support “Back” button to allow the user to step back during the simulation. The process is linear and does not allow for branching. To enhance the educational value of the lab, the developer may allow the user to make mistakes and go along a wrong branch, then retract and figure out where to make the correct turn. An instructor may want to know which stages of the mitosis process present the greatest difficulty for the student, so to give it greater coverage in the lectures. Hence, the system could be extended to maintain statistics about the number of errors the students perpetrate in each step. If a student Chapter 1 • Introduction 37 tries to skip the current stage before completing it or performs actions incorrectly, this is recorded in a database at a server. The error statistics would be made available to instructors. Another extension is to model the process of meiosis which involves two mitotic divisions. Additional Information See also Problem 2.10 and Problem 3.3 at the end of Chapter 2 and Chapter 3, respectively, the solutions of which can be found at the back of this text. Any cell biology textbook contains a description of the mitosis process. There is also a great deal of online information. Some examples are given at this book’s website. The reader may also find useful information in this article: R. Subramanian and I. Marsic, “ViBE: Virtual biology experiments,” Proceedings of the Tenth International World Wide Web Conference WWW10, Hong Kong, pp. 316-325, May 2001. Online at: http:www.caip.rutgers.edudisciplePublicationswww10

1.5.2 Project 2: Restaurant Automation

The goal for this project is to introduce automation in privately-owned restaurants, that is, small- to medium-sized establishments. Typical problems restaurant personnel are facing include: • Coordination of their work activities • Anticipating and handling periods of lowhigh patron traffic • Recognizing trends early enough to take advantage of bestsellers or abandon the flops • Lowering operating costs, and increasing efficiencyproductivity and profits Many restaurants are still operated using pen and paper methods, with little or no automation see Figure 1-19. Patrons enter the facility to be greeted by a host, who often times has a “dry erase” diagram of the tables, maintained on a blackboard. The host can see the status of the tables based on whether or not they or someone else physically updates the diagram. Once seated a waiter tends to the costumers by jotting down the orders onto a piece of carbon paper and delivers it to the kitchen for proper food preparation. The waiter then has to periodically check back to find out when the meal is ready. When the food is done, the piece of carbon paper is saved for proper record keeping by the management. This “old fashion” system works but yields a large amount of tab receipts, wastes a lot of time and is simply out-of-date. In old fashion systems, waiters have to carry pads around to take orders, always have a working pen and be sure to keep each bill organized and “synchronized” with the proper table. Another issue is record maintenance. In the old system, when everything is done by paper, the management is responsible to keep all information saved and organized, which is no easy task. Everyday tabs are collected, data needs to be organized and employees need to get paid. This requires a great deal of time and attention from the managers. This project computerizes restaurant operation so that all information pertaining to patron’s orders and staff activity will be conveniently shared and stored over the restaurant’s intranet. Hosts will be able to view table status with a click of a button. The wait staff will be able to enter Ivan Marsic • Rutgers University 38 the patron’s orders quickly and efficiently and then have it electronically delivered to the kitchen. The kitchen staff will be able to view the incoming orders and notify the proper wait staff when the food is ready. Bus boys will be able to view real-time floor status allowing them to know which tables are clean, dirty, or occupied. Most importantly, all of the restaurant information is organized and saved in the system database for the management viewing and archival. The analysis will consist of by-the-day and by-the-hour breakdowns of: • Revenue and revenue percentage per menu item • Menu item popularity • Personnel efficiency • Average turnaround time how long patrons spend in the restaurant • Average preparation time time from when the order is placed to when it is ready There is no more abundance of papers and long hours of punching numbers. All data is automatically collected and processed allowing management to focus on analyzing the data rather than calculating it. Statement of Requirements By using a touch screen the restaurant staff can quickly and efficiently log in and complete the desired task. When a waiter logs in, they are greeted with a floor status screen in which their assigned tables are colored in. Their tables are colored according to status; green is open, yellow is occupied, red is dirty see Figure 1-20. At this point a waiter can select a table to view its tab. Once a table is selected, the staff can choose from a number of options. If they select to add an item to the table’s tab, they are presented with various categories of food items offered. Here they can select the appropriate category and then find the desired item. For example, if a patron ordered a Caesar salad, the waiter would login, select the table, and choose “Add Item.” They would then select the “SoupsSalads” from the category list, and then select the desired salad from the items presented. They are then returned to that table’s screen where they can choose to perform another task or logout. This saves the waiter from walking back and forth to the kitchen to deliver and check up on food orders. Orders placed by wait-staff using the computer terminals Archiving When the customer pays, the tab can be kept for record-keeping Order queue Kitchen gets a copy, and returns it with the food Tab Waiter writes order on carbon paper Notification When the order is ready, the kitchen staff rings the call bell Figure 1-19: Old-fashioned restaurant operation. Chapter 1 • Introduction 39 on the restaurant floor are displayed to the kitchen staff through a queue, i.e., on a first-in, first- out basis. The supported employee roles are: Host, Waiter, Cook, Busboy, and Manager. Some of the direct links between some of the staff include: Host ↔ Waiter, Waiter ↔ Cook, and Busboy ↔ Host. Every user account in the system should have its own privileges. All the role-personalized home screens for each employee will be refreshed automatically when needed when a table is marked ready; a table’s order is prepared; a host assigns a waiter to a table; etc.. The Manager should have administrative power over employee profiles: the ability to create and modify profiles, track employee activities, and authorize restricted waiter activities. If the employee is a waiter, hisher profile also contains information about the tables for which heshe is responsible. From this profile, the individual tabs for those tables can be accessed. The manager should also have ability to manage other aspects of restaurant operations, such as inventory tracking and sale analysis. There is an important choice of the type of computer terminals used by the waiters. All other personnel are either stationary, e.g., kitchen staff and hosts, or can access information at stationary terminals, e.g., busboys. If the waiters are required to use stationary terminals, they must memorize or jot down a specific table’s order and then find an open computer, login and enter the information into the system. At this point everything else is done electronically. Another option is to have the waiters provided with handheld devices, which will be connected wirelessly to the rest of the system, completely eliminating the use of carbon paper. There are certain advantages of stationary computer terminals over handheld devices: i a small number of fixed terminals can be time-shared by multiple personnel, so this solution may be cheaper and easier to maintain; ii they are fixed, so they cannot be lost or damaged in handling. Thus, in the first instantiation we will assume fixed terminals for the entire staff. Throughout the restaurant there will be computer terminals for the staff to login. The system requires each user to login, complete their task and logout. Since this will require frequent logins and logouts, it may appear as an unnecessary overhead. With a limited number of terminals, staff will not be able to remain logged in since other employees need to use the computers. Logging in and out events can be exploited to trigger data updates and reorganization, as well as for Bar Salad Bar 2 2 1 1 4 4 3 3 8 8 7 7 1 1 6 6 7 7 9 9 10 10 15 15 16 16 17 17 19 19 20 20 12 12 14 14 13 13 11 11 Restaurant Floor Status Host Ready Occupied Dirty Assigned to Other Waiters Archiving Record-keeping is done by the server Order queue Kitchen staff views orders on a computer in the kitchen Tab Waiter places order at a computer on the restaurant floor Notification When the order is ready, the waiter will be notified the next time he logs in Figure 1-20: Restaurant automation facilitates staff coordination and record keeping.