Stock Average

Silver and Moon (J Opl Res Soc 50(8) (1999) 789–796) address the problem of minimising total average cycle stock subject to two practical constraints. They provide a dynamic programming formulation for obtaining an optimal solution and propose a simple and efficient heuristic algorithm.

Hsieh (J Opl Res Soc 52(4) (2001) 463–470) proposes a 0–1 linear programming approach to the problem and a simple heuristic based on the relaxed 0–1 programming formulation. We show in this paper that the formulation of Hsieh can be improved for solving very large size instances of this inventory problem. So the mathematical approach is interesting for several reasons: the definition of the model is simple, its implementation is immediate by using a mathematical programming language together with a mixed integer programming software and the performance of the approach is excellent.

Computational experiments carried out on the set of realistic examples considered in the above references are reported. We also show that the general framework for modelling given by mixed integer programming allows the initial model to be extended in several interesting directions.Journal of the Operational Research Society (2003) 54, 362–370. doi:10.1057/palgrave.jors.2601452

[Sigma Contract Specification]

Sigma Forex provide the clients with the lowest spreads in Forex Market for the most traded pairs and Forex spots.

Trading Hours
Sigma Dealing Room operate 24/5 from Sunday 23:00 CET until Friday 23.00 CET.
You Can contact us directly: + 41 435 004 145

Margin Requirements
The margin requirements must be respected by Friday at 23:00 GMT and before holidays.
One of our dealers will contact you if you are below your margin requirements at that time. Your margin requirements will depend on the client's account equity. However, if you approach the level where the loss of your open positions approaches the balance of your account, you will be stopped out and your positions will be closed. Stop positions will be executed when there is only around 50% equity of the required margin left in your account.

Streamline Dealing
Clients will not suffer Price Re-Quote that you can buy and sell directly on real-time prices without a request for quote (RFQ).
Clients taking advantage of wrong price quotes in the Market Watch will be requoted.
Sigma Forex effort is taken to ensure correct pricing at all times. However, there are rare circumstances when wrong prices are given.

Stop Order Execution
Volatile market conditions can result in prices gapping, which may prevent the execution of stop orders (sell stop, buy stop, stop loss) at the price you initially requested. However, our dealers strive to execute all stop orders at the price, or failing that, at the best attainable rate the market allows.

Lot Types
Sigma Forex has generated an ultimate account type that allow you to trade Standard, Mini and Micro lot in the same account which is Sigma Account to make it more simple and easy for traders.

Multi Currency Denomination

Sigma offers the ability to set-up accounts denominated in the following currencies:

• United States dollar (USD)
• Euro (EUR)
• Great Britain pound (GBP)
• Australian dollar (AUD)
• Swiss Frank (CHF)

There is no minimum deposit for opening an account, in order to review the spreads, pip value & margin requirement choose the required pair, leverage & the lot type.

If you have any problem regarding Sigma Contract Specification click on the Live Chat button on the right hand side and our customer support staff will help you through the process.