Jumat, 31 Maret 2017

PREPAREDNESS OF TORNADO DISASTER



Individual Assignment
Lecturer     :Ir. R. Didiet Hidayat



Name          : Hanifah Fiddieny

NIM           : 2244.14.101

Trisakti School of Transportation

March 2017




About
Tornadoes are violent: they can completely destroy well-made structures, uproot trees and hurl objects through the air like deadly missiles. Although severe tornadoes are most common in the Plains States, they can happen anywhere. Learn what to do to keep your loved ones safe.
Preparedness
Preparedness involves a continuous process of planning, equipping, training and exercising. Planning for tornadoes requires identifying a place to take shelter, being familiar with and monitoring your community’s warning system, and establishing procedures to account for individuals in the building. Employers may need to obtain additional equipment and/or resources (e.g. Emergency Supply Kits) identified in the plan. In addition, workers need to be trained and plans need to be practiced to ensure that personnel are familiar with what to do in the event of a tornado.
Planning
Identifying Shelter Locations
An underground area, such as a basement or storm cellar, provides the best protection from a tornado. If an underground shelter is unavailable, consider the following:
  • Seek a small interior room or hallway on the lowest floor possible
  • Stay away from doors, windows, and outside walls
  • Stay in the center of the room, and avoid corners because they attract debris
  • Rooms constructed with reinforced concrete, brick or block with no windows and a heavy concrete floor or roof system overhead
  • Avoid auditoriums, cafeterias and gymnasiums that have flat, wide-span roofs.
Personnel should also be aware of what to do if caught outdoors when a tornado is threatening. Seek shelter in a basement or a sturdy building. If one is not within walking distance, try to drive in a vehicle, using a seat belt, to the nearest shelter. If flying debris is encountered while in a vehicle, there are two options: 1) staying in the vehicle with the seat belt on, keeping your head below the windows and covering it with your hands or a blanket, 2) if there is an area which is noticeable lower than the roadway, lie in that area and cover your head with your hands.
Accountability procedures
The following steps are recommended to help ensure the safety of personnel if a tornado occurs:
Warning Systems
Tornado Watch - Tornadoes are likely to occur in the watch area. Be ready to act quickly and take shelter, and check supply kits. Monitor radio and television stations for more information.
Tornado Warning - Imminent threat - A tornado has been sighted in the area or has been indicated by radar. Take shelter immediately.
Your local emergency management office can provide information about your community’s tornado warning system.
  • Develop a system for knowing who is in the building in the event of an emergency
  • Establish an alarm system to warn workers
    • Test systems frequently
    • Develop plans to communicate warnings to personnel with disabilities or who do not speak English
  • Account for workers, visitors, and customers as they arrive in the shelter
    • Use a prepared roster or checklist
    • Take a head count
  • Assign specific duties to workers in advance; create checklists for each specific responsibility. Designate and train workers alternates in case the assigned person is not there or is injured
Some businesses are required to have an Emergency Action Plan meeting the requirements under 29 CFR 1910.38, see Evacuation Plans and Procedures eTool for more information. Though Emergency Action Plans primarily involve evacuations, emergency planning for tornadoes involve identifying safe places of refuge for workers to go to in the event of tornadoes.
Equipping
Training and Exercises
  • Ensure that all workers know what to do in case of an emergency.
  • Practice shelter-in-place plans on a regular basis.
  • Update plans and procedures based on lessons learned from exercises.
For more information, see the preparedness guide developed by NOAA, FEMA and the American Red Cross.
Additional guidance on emergency plans:

Thunderstorm Preparedness: A Guide to Storm Survival

Most thunderstorms are no big deal, right? Wrong. Every thunderstorm, no matter how big or how small, carries with it some danger.
From lightning strikes to high winds and even tornadoes, thunderstorms across the country cause property damage, cost Americans billions of dollars annually, and even take lives.
What’s more – they’re plentiful. About 16 million thunderstorms happen each year, with around 1,800 going on at any given time. That’s why it’s necessary to be prepared, and this guide will help you do that.
Tornado Preparedness

Why Prepare for Thunderstorms?

Though thunderstorms are dangerous, their power is often underestimated because they’re so common. Everyone experiences thunderstorms regularly, and that makes it easy to forget their unpredictability. Violent storms can cause a variety of other dangerous events, here are a few:
The number-one thing you can do to protect you, your family, and your belongings from the dangers of thunderstorms – or any natural disaster for that reason – is to be prepared. But what, exactly, does that mean?
Being prepared means having the knowledge and supplies necessary to stay safe and handle emergency situations to the best of your ability. It doesn’t always mean you’re going to be safe, but it does improve your chances.

Build an Emergency Preparedness Kit

The first thing you need to do to be prepared is have an emergency preparedness kit. This kit contains everything you and your family will need in an emergency, as well as enough supplies to survive for three to five days.
Here’s a list of items that every emergency preparedness kit should contain:
  • One gallon of water per person, per day
  • Around 2,000 calories of non-perishable food per person, per day
  • A mechanical can opener
  • First-aid supplies to handle minor injuries, including splints, suture kit, antibacterial creams, bandages, and antihistamine
  • Hand-crank or battery-operated radio, preferably a NOAA weather radio
  • A week’s worth of all prescription medications
  • Hygiene items such as toothpaste, shampoo, and feminine products
  • Copies of important documents in a waterproof container; be sure to include driver’s licenses, birth certificates, social security cards, and insurance cards
  • Blankets
  • Flashlights and extra batteries
  • A minimal amount of money in small bills
  • An extra credit card
  • Emergency contact list, including names, telephone numbers, and addresses
  • If you have children, include items to entertain them, such as coloring books, cards, or board games
  • If you have an infant, be sure to include diapers, formula, and anything else you’ll need
  • If you have pets, have enough food and other supplies for them
For the elderly or anyone with a disability, make sure to include items to meet their specific needs.

Before Severe Weather Hits

Preparation for severe weather, including thunderstorms and tornadoes, happens well before a storm is spotted. To be ready and stay safe, here are things you should do on a regular basis, before a storm hits:

Landscaping

Keeping your yard clean of dead trees and rotting limbs protects both you and your property. It reduces the risk of limbs falling onto a person, vehicle, or even your home. If a tree is starting to die, removing it from the property guarantees it won’t uproot or snap and fall during high winds.

Secure Outdoor Objects

When there’s a chance of severe weather, secure your outdoor items to the ground. From picnic tables to fuel tanks, high winds can topple and blow huge items around, causing damage and making cleanup more difficult. Take small, easy-to-move items indoors.

Watch vs. Warning

If your area is at risk of severe weather, know what to be prepared for. NOAA weather radios keep you informed of National Weather Service weather alerts. A severe weather watch means that conditions are right for severe weather to occur. A severe weather warning means that a thunderstorm has been reported or indicated by radar.
Just to clarify:
  • Watch = Possibility
  • Warning = Occurring

Keep Activities Inside

If there’s a thunderstorm risk, postpone any outdoor activities or make alternate plans. You don’t need 15 kids outside during a thunderstorm for a birthday party. Either have it another day or have a plan B just in case.

Protect Pets and Livestock

While it may seem that pets and livestock should be able to withstand a thunderstorm, animals should be put indoors and out of harm’s way. They are susceptible to being struck by lightning, especially those who reside in open fields. Hail can also be dangerous to livestock without cover, and can cause injuries or even be fatal.
To keep them safe, secure livestock in a sturdy building, with plenty of food and water.

During a Thunderstorm

The most severe storms occur when one storm lingers for an extended time over a specific area. Only 10 percent of all storms are considered severe, which indicates one of the following:
  • Hail with a diameter of at least one inch
  • 58-mph winds or greater
  • Produces a tornado
Because of their unpredictability, once a thunderstorm is in the area, there’s not much that can be done to prepare for the damage that may occur. Even so, there are things you can do to increase your chance of safety.

Head Indoors

If you can hear thunder, you’re within reach of lightning – which can travel up to 10 miles outside of the storm. Hence, the lack of rain or thunder is in the distance is not a sign of safety. As soon as a storm is in your area, it’s time to head inside. And inside means completely indoors, not on the back porch and not in the front door. While thunderstorms can be beautiful to watch, they’re dangerous. Even standing in front of a window can lead to unnecessary injuries.
Regardless of what urban myth you’ve heard, rubber soles and tires do not protect you from lightning, so don’t think wearing sneakers means it’s okay to continue your golf game. It’s not – ever.

Shutter Windows

Shutter your windows when the storm starts in order to protect them from high winds, hail, and debris. If you don’t have shutters, close the drapes or blinds for added protection. Be sure to stand away from other glass structures, including glass doors and skylights.

Unplug Electronics

Unplug electronic devices – including computers, television sets, and other items – that may be damaged if there’s a power surge or lightning strike. Avoid using items that plug in, as current can travel through them and shock you.

Avoid Corded Phones

If you need to make a phone call during a thunderstorm, do NOT use a corded phone or a cell phone that is plugged in. Electricity easily travels through phone lines and can actually electrocute you through the phone.

Avoid Plumbing

A thunderstorm is not the time to take a shower or do the dishes. The shock from lightning can travel through the water and pipes, making faucets and fixtures dangerous.

Avoid Concrete

When it’s storming, be sure to avoid laying on concrete floors or leaning on concrete walls. While concrete itself does not conduct electricity, it’s often reinforced with steel, which does.

Be Aware of Natural Lightning Rods

Lightning often strikes the highest thing available, so be aware of solitary trees, TV antennas, power lines, or other high structures. If outside, try to make yourself smaller than surrounding objects to avoid being struck by lightning.

If in a Vehicle

If you’re in a vehicle when a storm hits, turn on your flashers and pull over until you can safely see to drive. While the rubber tires of the vehicle do not protect you from lightning, the hard metal top does and makes your vehicle the second safest place to be during a thunderstorm. Just be sure you’re not touching any metal in the vehicle, and if you’re in a soft-top vehicle, seek shelter as soon as possible.

If in the Woods

If you’re in the woods when severe weather hits and are too far away to get to a building or vehicle, seek shelter in a low area, preferably under a thick cover of small trees. Try to avoid dead trees or hanging limbs.

If in the Open

If you’re in the open with no shelters or vehicles nearby, get as low as you can in a ravine or valley. Crouch down, staying on the balls of your feet, and cover your head, making yourself the smallest target possible. While this protects you from lightning and winds, be cautious of flash floods, which cause the most storm-related deaths in the U.S.

If in Open Water

Being in open water during a thunderstorm is perhaps one of the most dangerous places to be. Head toward land as soon as signs of a storm appear. Stay away from metal on the boat and phone in for assistance if necessary.

The Risks of Lightning

Lightning is one of the main reasons that thunderstorms are so dangerous, and is one of the top three causes for storm-related fatalities in the U.S., with an average of 51 deaths per year and hundreds of injuries.
Here are some lightning facts that are important to know:
  • Lightning occurs when there is a buildup and discharge of electrical energy.
  • While anyone can get struck by lightning, over 80 percent of fatalities are men, aged 15 to 40.
  • The chance of getting struck by lightning is one in 600,000.
  • Most lightning deaths and injuries occur in the summer when someone is stuck outside during a storm in the afternoon or evening.
  • Lightning heats the air around it to 50,000 degrees Fahrenheit, which is hotter than the surface of the sun.
  • Because this air is so hot, it produces a shockwave, which we hear as thunder.
  • There is no such thing as heat lightning; it’s actually regular lightning from a thunderstorm that’s too far away to be seen.
  • It doesn’t need to be raining for there to be lightning; dry lightning is particularly common in the Southwest, where the rain evaporates before hitting the ground.
  • To figure out how far lightning is, count the time between seeing the strike and hearing the thunder; every five seconds is about one mile.
There is a risk of being struck by lightning when any of the following occur:
  • You see lightning
  • You hear thunder
  • There’s a loud static on AM radio
  • There’s a buzz sound on the radio antenna
  • When the masthead on a ship begins to glow, which is also called St. Elmo’s Fire

If Struck by Lightning

If you’re with someone who’s been struck by lightning, here’s what you need to do to keep them safe:
  • A person struck by lightning does not hold an electric charge, so don’t be afraid to touch them.
  • Call 911 immediately.
  • Look to see if the individual is breathing; if not, perform mouth to mouth.
  • Check for a heartbeat; if you can’t find it, start CPR.
  • Look for burns where the lightning entered and exited the body
  • There may also be nervous system damage, broken bones, or trouble with hearing and eyesight.

Tornado Preparedness

One of the most dangerous aspects of thunderstorms is their ability to spawn tornadoes. A rotating column of air extending from a cumuliform cloud, tornadoes are destructive forces that can be over a mile wide and extend for over 50 miles with winds in excess of 200 mph. While tornadoes can happen anywhere in the world, they most often occur in the U.S., with an average of about 1,200 per year.
Tornadoes typically occur when it’s warm, humid, and windy, and can also be formed from hurricanes and tropical storms. While the tornado itself is extremely dangerous, most damage occurs from the strong winds and flying debris carried by the tornado.
Since tornadoes form from severe thunderstorms, the precautions associated with storms should also be followed for tornadoes, along with the following:

Basement

Anytime there’s a chance of a tornado, you want to do more than just head indoors – you want to get to the lowest floor possible, preferably underground. Once there, get under a workbench to protect yourself from falling debris. If that’s not available, cover yourself with a mattress.

Interior Room

If your home does not have a basement, move to a small, interior room with no windows. Do not worry about opening up windows or leaving doors open. Most buildings have enough leaks that the air does not pressurize to the point of breaking glass.
If you don’t have an appropriate interior room, hallways, under stairwells, and even bathtubs offer some protection during a tornado.

Safe Room

Often used in mobile home parks and community buildings, safe rooms are specifically designed to provide more safety during severe weather and tornadoes. These rooms are reinforced and designed to withstand high winds. If you do build a safe room, be sure to register it with your local fire department. That way if an emergency occurs and you get trapped in the room, the authorities will know where to look.

Assume the Position

Whether you’re in a basement or school hallway, get into a crouched position against a wall or solid structure. Cover your head and neck with your arms, and if it’s available, cover yourself with a mattress, blanket, or even towels.
Be sure to position yourself in a place that isn’t below heavy objects on the above floors. Things like pianos and waterbeds have been known to fall through floors during tornadoes, and can cause significant and even fatal damage.

Mobile Homes

Mobile homes and travel trailers are NEVER safe places to be during a tornado. Even if the building is strapped to the ground, these structures are often lifted and thrown. If you live in a mobile home, be sure to have an outdoor safe room or a place to go underground in the chance of a tornado.

Vehicle

If you find yourself in a vehicle and a tornado is approaching, seek shelter in a sturdy building immediately. If that’s not possible, you have a few different options depending on your situation:
  • Outdrive it: If the tornado is far enough away and you think you can outrun it in your vehicle, do so. Move away from the tornado at 90 degree angles. Remember, tornadoes change directions frequently and without warning. It is NEVER safe to move toward a tornado for any reason.
  • Secure yourself inside: If there’s no building nearby and the tornado is too close to drive away, secure yourself inside the vehicle. Put your seatbelt on, and lower yourself so your head and body are below the windshield. Protect your head and neck by covering them with your arms, and cover yourself with a blanket or jacket if possible. Vehicles often get lifted and tossed by tornadoes, but securing yourself inside lowers your risk of injury or death.
  • Get lower: The only time you should leave your vehicle during a tornado is if you can get lower than the roadway. If there’s a ditch or ravine, get in it, and cover your head. If there’s something secured to the ground that you can get near or hold on to, do so. Be sure to avoid areas where things could topple on top of you. Bridges and underpasses are NOT safe and too often collapse to offer any safety.

Outdoors

If you’re stuck outside during a tornado and there’s no building or vehicle to get to, get in the lowest place you can find. A ditch, valley, or ravine offer some protection against the elements. Try to avoid places with debris that can be picked up by the tornado.

Pets and Livestock

During severe weather, animal behaviors change. They become nervous, agitated, and may be impossible to keep calm. Animals often sense tornadoes well before people do, so be prepared that it may be more difficult than normal to handle them.
If a tornado is in the immediate vicinity, do not worry about your livestock. Animals are not worth risking your own or your family’s safety. That being said, if time allows, here are some things you can do to increase safety for your livestock during a tornado:
  • Never leave animals tied up or restrained outside.
  • If time is limited, open up escape routes, allowing your animals to get to safety on their own.
  • If you have a barn or building that is secure, bring animals into the shelter and provide food and water before the storm hits.

After a Tornado

Thunderstorm Preparedness: A Guide to Storm SurvivalAfter a tornado passes, it’s time to evaluate the damage and offer assistance to those who need it. First and foremost, seek medical attention for those who are injured. Emergency personnel may have trouble reaching people, so keep your emergency preparedness kit with you.
If your home is still standing, don’t assume everything is okay. Buildings get hit with projectiles and often suffer structural weaknesses during tornadoes. Just because it’s still standing does not mean that it’s safe. Proceed with caution.
Tornadoes can also expose homes, water supplies, and communities to hazardous materials. Be sure to talk to local authorities about proceeding when this occurs.

Protect Yourself with Preparedness

While there’s nothing that can guarantee your safety when an emergency hits, being prepared is your best bet. And when it comes to thunderstorms and tornadoes, being prepared can mean the difference between survival and death. That’s why it’s so important to protect yourself and those you love by staying prepared for the elements.

Jumat, 08 April 2016

Economic Order Quantity

EOQ (Economic Order Quantity) is a model that involves the procurement of raw materials or stock in a company. Every industrial company certainly require raw materials for smooth business processes, the raw materials obtained from suppliers with a certain calculation. By using the calculations, a company can economically regularly determine how and how much material must be provided. Irregularities scheduling will impact on inventory costs due to accumulated inventory in the warehouse. Thus arrangement of raw materials is one of the important things and can provide benefits to the company.

In defending the life cycle of a company, inventory is one component that really need to be considered and planned with very mature. Delays in delivery of raw materials or items needed can complicate the performance of the company. Necessary materials should also be stored on a seasonal basis for avoiding price increases. Companies are racing to prepare inventories of goods they use a lot of things and methods. One method used by the company in minimizing risk in the process of inventory is the method of EOQ (Economic Order Quantity). Economic Order Quantity is a method used to optimize the purchase of raw materials which can reduce inventory costs so that the efficiency of material inventory in the company can run well. The use of EOQ method can assist a company in determining the number of units ordered in order to achieve a booking fee and inventory costs to a minimum. Some advantages which may be granted by the EOQ are to eliminate the risk if materials ordered are not good so it must be restored, eliminating the risk of price increases on a seasonal basis or inflation, store raw materials produced on a seasonal basis so that the company will have no trouble if the material was not available on the market, and others.

Economic Order Quantity first developed by F. W. Harris in 1915 to develop the economic order quantity formula. It is one of the oldest models of classical production scheduling. The framework used to determine the order quantity is also known as Wilson EOQ Model or the Wilson Formula.


Definition According to Prof. Dr. Bambang Rianto Economic Order Quantity is the quantity of goods that can be obtained with minimal cost, or often said to be the optimal number of purchases.


Definition According to Drs. Agus Ahyadi Economic Order Quantity is the number of purchases of raw materials that can provide minimal inventory costs. Of the two definitions above, it can be concluded that the EOQ is a method used to optimize the purchase of raw materials which can reduce inventory costs so that the efficiency of material inventory in the company can run well.


The purpose of the EOQ model is to minimize the total cost of inventory. Important cost is the cost of the reservation, the cost of placing the order, and the cost of carrying or holding units of inventory in stock. All other costs such as, for example, the purchase cost of inventory itself, which is constant and therefore not relevant to the model. The booking fee is also known as the cost of purchase or cost of set up, this is the amount of fixed costs that occur each time an item was ordered. These costs are not related to the quantity ordered but especially with physical activity required to process the order. The carrying cost is also called storage costs, carrying costs are the costs associated with inventories having on hand. It mainly consists of costs associated with inventory investment and storage costs. For the purposes of calculating the EOQ, if the cost does not change based on the amount of inventory on hand does not have to be included in the carrying cost. In the EOQ formula, the cost of bringing represented as the average annual cost per unit of inventory on hand. The following are the main components of carrying cost.

  • Interest

If you need to borrow money to pay for your supplies, the interest rate will be part of the carrying value. If you do not borrow on inventory but have a loan on other capital goods, you can use the mortgage interest rate for inventory reduction will free up money that could be used to repay the loan. If by some miracle you are debt free you will need to determine how much you could make if the money was invested.


  • Insurance

Because insurance costs are directly related to the total inventory value, you would include this as part of the carrying cost.


  • Tax,

If you are required to pay tax on the value of your inventory they will also be included.

Variables
·        P = purchase unit price, unit production cost
·        Q = order quantity
·        Q* = optimal order quantity
·        D = annual demand quantity
·        K = fixed cost per order, setup cost (not per unit, typically cost of ordering and shipping and handling. This is not the cost of goods)
·        h= annual holding cost per unit, also known as carrying cost or storage cost (capital cost, warehouse space, refrigeration, insurance, etc. usually not related to the unit production cost)

The Total Cost function and derivation of EOQ formula

Classic EOQ model: trade-off between ordering cost (blue) and holding cost (red). Total cost (green) admits aglobal optimum. Purchase cost is not a relevant cost for determining the optimal order quantity.

The single-item EOQ formula finds the minimum point of the following cost function:
Total Cost = purchase cost or production cost + ordering cost + holding cost
Where:
·         Purchase cost: This is the variable cost of goods: purchase unit price × annual demand quantity. This is P × D
·         Ordering cost: This is the cost of placing orders: each order has a fixed cost K, and we need to order D/Q times per year. This is K × D/Q
·         Holding cost: the average quantity in stock (between fully replenished and empty) is Q/2, so this cost is h × Q/2

To determine the minimum point of the total cost curve, calculate the derivative of the total cost with respect to Q (assume all other variables are constant) and set it equal to 0:

Solving for Q gives Q* (the optimal order quantity):

Therefore:

ECONOMIC ORDER QUANTITY


The optimal value Q* may also be found by recognising that
[3]Q* is independent of P; it is a function of only K, D, h.

 where the non-negative quadratic term disappears for 
 which provides the cost minimum 


Example: 
PT Feminine is a company that manufactures a lady bag. The company requires a material component as many as 12,000 units a year. The booking fee component was Rp. 50,000 for each booking, regardless of the number of items ordered. Storage costs (per / unit / year) of 10% of the inventory value. Price component USD. 3,000 per unit.
Based on that data, the company's managers can determine the most economical order quantity (EOQ) that can provide the lowest total cost of inventory. EOQ calculations to obtain in this case can be seen in Table:



D = 12000 unit
K = Rp. 50.000
h = 10%
C = Rp 3.000
H = Cx h = 300

EOQ = 2 X 12000 X 50000 = 2000 unit
                        300

The most economical frequency bookings are:
 F* = D    = 12000 = 6 times/year
       EOQ     2000

If one year is equal to 365 days the time period between each order is:
T* = working days per year = 365 = 61 days
                        F*                      6

REORDER POINT
In order for the purchase of materials that have been defined in the EOQ not interfere
smooth operation of the production, it will take a re-ordering of materials
raw. Factors that influence the reorder point is:

1. Lead Time. Lead time is the time taken between the raw materials ordered
up to the company. Lead time will affect the amount of raw materials
used during the lead time, the longer the lead time it will be more
Great material needed during the lead time.

2. The rate of raw material consumption average of unity given time.

3. Inventory Safety (Safety Stock), the amount of the minimum supply of materials
must be owned by the company to maintain the possibility of delays in the arrival of
raw materials, so there is no stagnation. Of the three factors above,
reorder point can be searched by the following formula:

Reorder Point = (LD x AU) + SS
LD = Lead Time
AU = Average Usage Average Usage =
SS = Safety Stock

example:

PT. Deivy assign a lead time of raw material for 4 weeks, the average consumption of 250 kg per week, safety stock is valued at the average usage for 2 weeks. From this data, then reorder pointnya are as follows:
Reorder Point = (4 x 250) + (2 x 250)
= 1500

SAFETY STOCK

To estimate the amount of safety stock, can be used relatively more thorough way is by the method as follows:
1.Metode Usage Difference Maximum and average.
This method is done by calculating the difference between the maximum usage
average usage within a specified period (eg weekly), then
The difference is multiplied by lead time.

Safety Stock = (Maximum Usage - Usage Average) Lead Time

Suppose PT. General estimates the maximum use of materials per week
650 kg, while the average consumption of 500 kg and the long lead time 2
weeks, then the data safety stock of:
Safety Stock = (650-500) 2
= 300 Kg

2. Statistical Methods. To determine the amount of safety stock with this method,
then can use computer programs squares (least square). For
describes the use of this method, the following examples are given, namely
to assess the safety stock in 2001 based on 2000 data.

A---------B-----------C-----------D-------------E 
1-------2.600-------2.500-------100----------10.000
2-------2.300-------2.350-------(-50)---------2.500
3-------2.200-------2.350-------(-150)-------22.500
4-------2.400-------2.450-------(-50----------2.500
5-------2.750-------2.700-------50------------2.500
6-------2.500-------2.600-------(-100)-------10.000
7-------2.250-------2.300-------(-50)---------2.500
8-------2.400-------2.600-------(-200)-------40.000
9-------2.550-------2.400-------150----------22.500
10------2.250-------2.200-------50------------2.500
11------2.300-------2.340-------40------------1.600
12------1.500-------1.690-------(-190)-------36.100

Amount--26.000-----28.480-------(-480)------155.200

Eplanation:
A; Month
B; Estimated Usage
C; Actual Usage
D; Deviation
E; Quadratic Deviation



Steps calculate Safety Stock:
1. Calculate the average deviation = - 480: 12 = 140
2. Calculate the difference between total deviation squared squared with a total deviation
divided by n

(-480) 2
= -------- = 136 000 155 200
n

3. The results of the second step divided by n-1 and the results diakar squares.

136 000
= √ -------------------- = 111.19
12-1

4. To calculate the amount of safety stock is influenced by two factors:

a. The magnitude of a significant degree of standard deviation in a normal curve is used,
eg 97% = 2 or 99.5% = 3

b. The length of the time period used as a basis for calculation. Suppose degrees
Significant use of 99.5%, and long-term time basis during 4
month, then the safety stock:

= (3 x 111.19 x √4) - (-40 x 4) = 827.14


JUST IN TIME

JIT is an approach to minimize the total cost of storage and preparation which is very different from the traditional approach. The traditional approach acknowledges the cost of preparing and then determines the quantity of the order which is the best balance of the two categories of costs. On the other hand, the JIT does not recognize the cost of preparation, but instead JIT try to suppress these costs to zero. If the setup costs are not to be significant, then the remaining cost to be minimized is the cost of storage, which is done by reducing inventory up to quite low levels. That is the approach that is pushing for zero inventory in the JIT system.
Most of the production stoppage occurs for one of three reasons: the engine failure, material damage, and the unavailability of raw materials, so has the inventory is one of the traditional solution to all these problems. Those who support the JIT approach found many supplies that will not solve the problem, but only a disguise or cover up the problem. JIT can solve these three problems above with an emphasis on total maintenance and total quality control and establish a good relationship with suppliers.

6.ANALISIS ECONOMIC ORDER QUANTITY (EOQ)

A standard deviation calculation raw

D = D = å FD2
-----
n

d = standard deviation
f = Frequency of events
d = deviation from average incidence
n = Total observations provided

According to the table above example, the calculation of standard deviation obtained as follows:
181
d = å --------
28

= Ö 6:46
= 2.54

As a practical safety stock rounded to 3.
If the buffer stock set three, the security against less inventory will be 68.27%, while if used standard deviation 2, then the amount to be 6 then the seat will be 95.45%.
The same mechanism can we do to deviations from the replenishment cycle. By adding both safety stock is sourced from recycling irregularities and deviations requests recharging, the safety stock can be established.

Large Inventory Must Built

In building supplies are closely related to several factors as follows:

a. Cost and risk of storage
The greater the amount of drug that is stored, the greater the risk of missing the drug, the greater the risk of expired due to the slow adoption, as well as basically the same drug store to save money. Private storage environment that does not generate money or unproductive would be a waste of existing resources.

b. The booking fee.
For reservations drugs are available various administrations to monitor inventory, administration building to make a reservation or request, hire people to do the administration and provide forms for those needs.

c. Maintenance cost.
Warehouse facilities and infrastructure necessary maintenance and is in need of funds.

The greater the supply means the risk and the amount of storage facilities to be built and in need of maintenance to be larger, but on the other hand the cost of ordering and distribution costs become smaller.
This means that the need for optimization of this equation in order to achieve a balance between building inventory and distribution costs and reservations.

Mathematically the calculation formula defined in the Order Amount economic or formula known as Economic Order Quantity (EOQ).

2 Co S
EOQ = √ -----------
cm U

Co = Cost per Order (all messages)
Cm = Cost of Maintenance of the inventory in a year
S = Number of requests a year
U = Cost per unit



example:
The volume of requests a month in 2400 units
Price per unit Rp. 5, -
The maintenance fee of 20% means that the cost of providing such goods
is because the money had actually absorbed by the product should be subject to
interest, in this case the Bank's interest.
The booking fee is Rp. 20, -
Substituting these figures into the formula EOQ was then
obtained the following results:


EOQ = √ 2 x 20 x 2400
-------------
0:20 x 5:00
EOQ = √ 96,000
EOQ = 310

To make it easier we round it off to 300.

This means that the inventory should be built is 300 and this means that the average inventory will be 150 in one cycle of charging.