کاربرد آمار و احتمالات در مدیریت تنش سرما و یخ زدگی 19 ص

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1- مقدمه

با توجه به اهمیت و حساسیت امر مهار آب‌های سطحی خصوصاً در کشور ما که اکثر رودخانه‌های مناطق مختلف فصلی بوده و کمبود آبی که در پهنه وسیعی از کشور وجود دارد ، نیاز به شناسایی و به مدل در‌آوردن رفتار رودها و شریان‌های آبی جهت برنامه‌ریزی‌های بلندمدت و استفاده بیشتر و بهتر از پتانسیل‌های آنها عمیقاً احساس می‌شود . جدیدالتاسیس بودن بیشتر ایستگاه‌های هیدرومتری ، نواقص موجود در آمار اکثر این ایستگاه‌ها ، قرارگرفتن بیشتر رودها در مناطق خشک ، وضعیت بحرانی برداشت آب‌های زیرزمینی و لزوم توجه بیشتر به آب‌های سطحی همه‌ و همه دلایل بیشتر و ظریف‌تری می‌باشد که به مقوله پیش‌بینی و تولید آمار مصنوعی‌ در حوزه‌های آبریز کشورمان جلوه و نمودی کامل‌تر می‌بخشد .

روش‌های متداول آماری و احتمالی بر پایه روابط و فرمول‌های صرفاً ریاضی که به طور اخص به پیش‌بینی سری‌های زمانی می‌پردازد ، از دیرباز مورد توجه مهندسین علوم آب قرار گرفته است . آنها با دست‌مایه قراردادن این بخش از علم آمار به تحلیل ، بررسی و شناخت رفتار رودخانه‌ها می‌پرداختند . در این راستا نرم‌افزارهای مختلفی نیز تهیه وتنظیم شده که از مهم‌ترین و بارزترین آن‌ها می‌توان SPIGOT و HEC4 را نام برد .

شبکه عصبی مصنوعی نامی نوین در علوم مهندسی است که به‌طور ابتدایی و آغازین درسال 1962 توسط فرانک روزن بلات و در شکل جدی و تأثیرگذار در سال 1986 توسط رومل‌هارت و مک‌کلند با ابداع و ارائه مدل پرسپترون بهبود یافته به جهان معرفی شد . این شیوه از ساختاری نرونی و هوشمند با الگوبرداری مناسب از نرون‌های موجود در مغز انسان سعی می‌کند تا از طریق توابع تعریف شده ریاضی رفتار درون‌سلولی نرون‌های مغز را شبیه‌سازی کند و از طریق وزن‌های محاسباتی موجود در خطوط ارتباطی نرون‌های مصنوعی ، عملکرد سیناپسی را در نرون‌های طبیعی به مدل در آورد. ماهیت و ذات تجربی و منعطف این روش باعث می‌شود تا در مسائلی مانند مقوله پیش بینی که یک چنین نگرشی در ساختار آن‌ها مشاهده می‌شود و از رفتاری غیرخطی و لجام‌گسیخته برخوردار هستند ، به خوبی قابل استفاده باشد .

2- شبکه های عصبی مصنوعی

2-1- مفاهیم پایه در شبکه های عصبی مصنوعی

یک نرون بیولوژیک با جمع ورودی‌های خود که از طریق دندریت‌ها با یک وزن سیناپسی خاص به نرون اعمال می‌شوند ، با رسیدن به یک حد معین تولید خروجی می‌کند . این حد معین که همان حد آستانه می‌باشد ، در حقیقت عامل فعالیت نرون یا غیر فعال بودن آن است .

با توضیحات فوق می‌توان گفت که در مدل‌سازی یک نرون بیولوژیک به طور مصنوعی می‌بایست به سه عامل توجه شود :

نرون یا فعال است یا غیر فعال

خروجی تنها به ورودی‌های نرون بستگی دارد

ورودی‌ها باید به حدی برسند تا خروجی ایجاد گردد]1[.

2-2- شبکه عصبی پرسپترون ساده

فرانک روزن بلات ، با اتصال این نرون‌ها به طریقی ساده پرسپترون را ایجاد و ابداع کرد ، و برای نخستین بار این مدل را در کامپیوترهای دیجیتال شبیه‌سازی و آن‌ها را به طور رسمی تحلیل نمود]1[.

2-3- شبکه عصبی پرسپترون چند لایه ) MLP (

در بسیاری از مسائل پیچیدة ریاضی که به حل معادلات بغرنج غیر خطی منجر می‌شود ، یک شبکة پرسپترون چند لایه می‌تواند به سادگی با تعریف اوزان و توابع مناسب مورد استفاده قرارگیرد . توابع فعالیت مختلفی به فراخور اسلوب مسئله در نرون ها مورد استفاده قرار می‌گیرد . در این نوع شبکه‌ها از یک لایة ورودی جهت اعمال ورودی‌های مسئله یک لایة پنهان و یک لایة خروجی که نهایتاً پاسخ‌های مسئله را ارائه می‌نمایند ، استفاده می‌شود.

گره‌هایی که در لایة ورودی هستند ، نرون‌های حسی و گره‌های لایة خروجی ، نرون‌های پاسخ ‌دهنده هستند . در لایة پنهان نیز ، نرون‌های پنهان وجود دارند]2[.

آموزش این‌گونه شبکه‌ها معمولاً با روش پس انتشار خطا انجام می‌شود . نمونه‌ای از یک شبکه پرسپترون چند لایه در زیر نمایش داده شده است . شکل (1).

شکل 1- ساختار پرسپترون چندلایه با نرون‌های پنهان tansigو نرون‌های خروجی با تابع خطی]3[.

شبکه‌های پرسپترون چند لایه می‌توانند با هر تعداد لایه ساخته و به کار گرفته شوند ، ولی قضیه‌ای که ما در این‌جا بدون اثبات می پذیریم بیان می‌کند که یک شبکه پرسپترون سه لایه قادر است هر نوع فضایی را تفکیک کند . این قضیه که قضیة کولموگوروف نامیده می‌شود ، بیانگر مفهوم بسیار مهمی است که می‌توان در ساخت شبکه‌های عصبی از آن استفاده کرد]1[.

نوع خاصی از شبکه‌های عصبی چند لایه به نام پرسپترون تک لایه

) SLP (می‌باشد . این شبکه از یک لایة ورودی و یک لایة خروجی تشکیل شده است .

3- شرح تحقیق

تحقیق سرما زدگی سیب و سیب

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This article is about the computer company. For the multimedia corporation founded by The Beatles, see Apple Corps. For other companies also named Apple, see Apple (disambiguation).

Apple Inc. (NASDAQ: AAPL) is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include Macintosh computers, the iPod, the iPhone and the iPad. Apple software includes the Mac OS X operating system; the iTunes media browser; the iLife suite of multimedia and creativity software; the iWork suite of productivity software; Aperture, a professional photography package; Final Cut Studio, a suite of professional audio and film-industry software products; and Logic Studio, a suite of audio tools. As of January 2010 the company operates 284 retail stores[2] in ten countries,[6] and an online store where hardware and software products are sold.

Established on April 1, 1976 in Cupertino, California, and incorporated January 3, 1977,[7] the company was called Apple Computer, Inc. for its first 30 years, but removed the word "Computer" on January 9, 2007,[8] to reflect the company's ongoing expansion into the consumer electronics market in addition to its traditional focus on personal computers.[9] As of September 26, 2009, Apple had 34,300 full time employees and 2,500 temporary full time employees worldwide[10] and had worldwide annual sales of $42.91 billion in its fiscal year ending September 26, 2009.[3] For reasons as various as its philosophy of comprehensive aesthetic design to its distinctive advertising campaigns, Apple has established a unique reputation in the consumer electronics industry. This includes a customer base that is devoted to the company and its brand, particularly in the United States.[11] Fortune magazine named Apple the most admired company in the United States in 2008, and in the world in 2008, 2009, and 2010.[12][13][14] In May 2010, Apple's market cap exceeded that of Microsoft for the first time since 1989.[15]

سیب (نام علمی: Malus domestica) یک میوه درختی سردسیری از خانواده گلسرخیان است که انواع مختلفی دارد، مانند سیب گلاب(Gala apple)، سیب سرخ، سیب سبز و سیب وحشی. این میوه خوش عطر و طعم حاوی مقدار زیادی پتاسیم، سدیم، کلسیم، برم و فسفر و مقادیر زیادی ویتامین آ و ب می‌باشد.

خواص شیمیائی

سیب دارای ویتامین و مواد مغذی زیادی است و بی‌مناسبت نیست.

موادی که در یک سیب متوسط وجود دارد به شرح زیر است:

انرژی ۲۵۸ کالری

پروتئین ۱/۲ گرم

چربی ۱/۶ گرم

مواد نشاسته‌ای ۵۹/۶ گرم

کلسیم ۲۴ میلی گرم

فسفر ۱۰ میلی گرم

آهن ۱/۲ میلی گرم

ویتامین آ ۳۶۰ واحد

ویتامین ب ۱ ۰/۱۵ میلی گرم

ویتامین ب ۲ ۰/۰۸ میلی گرم

ویتامین ب ۳ ۰/۱ میلی گرم

ویتامین ث ۱۸ میلی گرم

ناگفته نماند که ویتامین‌های موجود در سیب بیشتر در پوست سیب و زیر پوست آن قرار دارد بنابراین آنهایی که می‌توانند پوست سیب را هضم کنند بهتر است که آنرا با پوست بخورند و اگر می‌خواهید پوست آن را بکنید بهتر است که سیب را خیلی نازک پوست کنید.

خواص داروئی

سیب یک میوه قلیایی است و تمیزکننده بدن است و به‌علت دارا بودن پکتین زیاد آب اضافی بدن را خارج می‌سازد

سیب را می‌توان برای برطرف کردن اسهال حتی برای کودکان به‌کار برد. بدین منظور سیب را باید رنده کرد و استفاده نمود. سیب را می‌توان پخت و برای آنهایی که روده تنبل دارند آن را روی آتش ملایمی بپزید البته حتماً از ظرف لعابی یا تفلون استفاده کنید زیرا به این طریق پکتین و ویتامین‌های آن حفظ می‌شود.

شربت سیب بهترین دارو برای درمان سرفه و گرفتگی صدا می‌باشد. برای تهیه شربت سیب یک کیلو سیب را شسته و با پوست قطعه قطعه کنید و در یک لیتر آب بپزید سپس آن را با پارچه نازکی صاف کنید و چند تکه قند به آن اضافه کنید و دوباره روی آتش ملایم قرار دهید تا قوام بیاید و آن را از روی آتش بردارید روزی سه تا چهار فنجان از این شربت بنوشید.

تنظیم گرما و سرما در ساختمان

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Designs That WorkVery Cold Climate

The Basic House - Mechanical Systems

As with the building enclosure design, working towards energy efficient mechanical systems is also very important in reducing the overall building energy consumption. Creating efficient mechanical systems is not just a matter of using high efficiency units; the overall system strategy, the location of the equipment and ducts, and the design of the distribution systems all impact the efficiency of the design. This section examines the impacts of efficient mechanical systems through examining the design of the cooling, heating, ventilation, dehumidification, and domestic hot water systems.

Prior to deciding on the specific system design for a house, a calculation should be made as to the maximum heat loss and heat gain of the house to determine how much energy the mechanical system needs to transfer to provide indoor comfort. The Air Conditioning Contractors of America has developed a methodology titled Manual J, which calculates the heating and cooling loads by taking into account the characteristics of the building enclosure. With this information, the system type and size can be determined depending on other constraints.

There are numerous methods for creating and distributing heating and cooling energy within homes, each with their own set of benefits and compromises. The primary decisions about mechanical systems tend to be controlled by available fuels, and by programmatic considerations. In general, there are two types of distribution systems – air based systems and water based systems. While heating can be accomplished with either system, cooling has thus far primarily been provided by air based systems due to the considerations with humidity. In this case, there is essentially no cooling required, so a radiant heating system was chosen.

With a tight building enclosure, mechanical ventilation and pollutant source control is also required to ensure that there is reasonable indoor air quality inside the house. A further consideration with the space conditioning system is how it might inter-relate with the mechanical ventilation system. Ventilation air flows are relatively small, and could be accomplished with smaller ducting, but there are certain advantages to coupling the space conditioning and ventilation systems. Exhaust fans located at potential pollutant sources can minimize the need for ventilation, but make-up air must also be considered for the air exhaust fans remove from the house.

In order to ensure good indoor air quality, all combustion appliances are recommended to be sealed combustion to the outdoors. These systems are completely decoupled from the interior environment through the use of dedicated outdoor air intake and exhaust ducts connected directly to the unit. Not only are the combustion products decoupled from the interior environment and concerns of back-drafting of the unit removed, but the usual make up air ducts soft connected to an area near the combustion appliance are eliminated. These make up air ducts (required for naturally aspirated units) are a source of uncontrolled air leakage through the building enclosure, and therefore increase utility use. Finally, the sealed combustion appliances tend to be more efficient than the naturally aspirated units.

Forced air systems can integrate the heating and cooling requirements as well as the ventilation requirements into one system, and therefore are often more cost effective than other specialized heating systems. Intermittent central-fan-integrated supply, designed to ASHRAE 62.2 ventilation requirements, with fan cycling control set to operate the central air handler is recommended to provide ventilation air, distribution, and whole-house averaging of air quality and comfort conditions.

Also, an integrated space conditioning and ventilation system is more likely to be serviced, and provides whole house mixing of indoor air. However, if a cooling system is not being installed, then a water based distribution system can be used instead, with smaller ventilation system ducting, and potentially a Heat Recovery Ventilator (HRV) to economize on heat used for ventilation air.

Typically, cooling requires a ducted air conditioning system, and the use of electricity. Depending on the climate, it may also make sense to use electricity and the ducted system to provide heating, in the form of an air source heat pump (ASHP), or ground source heat pump (GSHP). Where there is significant heating required, and natural gas is readily available, the performance of an ASHP or cost of a GSHP may prove to have a higher life-cycle cost than a condensing furnace. In the case where a cooling system is not desired, the duct system can either be downsized, or deleted and a hot water or radiant system can be used instead.

The location of the duct system can have a significant impact on the overall performance of the system, both the utility use and the ability to provide comfort. The energy loss from the ducts for forced air heating and cooling systems can be significant depending on the location of the ducts, and how well the ducts are sealed against air leakage. Though it is conceptually easy to imagine sealed duct systems, it is uncommon to find tight duct systems, and more common for duct leakage values of 20% of system flow. In many houses, the distribution duct work is located either in a vented crawl space or in a vented attic – effectively outdoors. With the ducts located exterior of the thermal envelope of the home, any leakage and conductive losses from the duct work is lost directly to the outside.

Moving the duct work and air handlers inside the thermal envelope or extending the thermal envelope to include areas such as crawl spaces and attic as part of the conditioned space of the house can be used to help prevent this energy loss to the exterior.

In general, the placement of the mechanical equipment will depend on the design of the house. For houses with conditioned crawlspaces and basements, it is often logical to place the air handler or furnace in those locations. For slab on grade designs or elevated floors, space can become a concern, in which case unvented attics provide for a convenient location for the mechanical equipment and ducts. Otherwise, placement of the equipment and / or ducts in a dropped ceiling or in closets is sometimes necessary. Consideration for space requirements for the mechanical equipment should be made early in the design. The following case study house was designed with a radiant heating system and small ventilation ducting, so that the duct work and mechanical equipment was able to be located inside the conditioned space.

Figure 22: Mechanical Schematic for Very Cold Climate House

Cooling System

Part of the America Benchmark Protocol requires the inclusion of a central cooling system on both the Benchmark and Prototype designs. To this end, the energy simulation calculations reflect the use of a central cooling system. Looking at the loads however, the cooling load is much less than 1% of the total yearly heating and cooling loads for the house located in Juneau, AK, with the heating makes up the remaining over 99%. Since the cooling is such a small portion of the load, no cooling system was actually included in this design.

Heating System

The heating system chosen is an 85% AFUE sealed combustion oil fired hot water heater, both for the availability of oil for heating, and the small size of the components of the system. The high efficiency oil boiler (in this case a Toyotomi Oil Miser OM-180) is somewhat of a specialty item, but is a good option for the cost and sealed combustion. The selected unit should be a sealed combustion unit with the dedicated intake and exhaust ducts connected to the outside to avoid any potential for back-drafting combustion products into the house.

The choice of a heat distribution system in the case of this prototype isn’t impacted by a need for cooling, and space is at somewhat of a premium, so baseboard finned tube radiators are being used for heating. Heat will be distributed around the house using baseboard finned tube radiators, which has been sized for a lower water temperature to allow integration with the hot water system, and higher efficiency. Standard baseboard radiators similar to Slant Fin BaseLine 2000 could be used with length shown on the drawings in the Appendices.

Duct Distribution System

With no need for cooling duct flows, the duct system can be significantly downsized to meet only the modest ventilation needs of the house. Small ducts are run from the outdoor air intake and exhaust hoods to the HRV, with supply air to the bedrooms of the house, and exhaust air from the common space. With the small flows expected from the HRV, the undercut on doors can easily handle the return air flow, avoiding the need for any further means of return.

Ventilation

The heart of the ventilation duct system is an HRV with flow ratings in the ~40-50 CFM range. Using the duct system described above, the objective is to turn over air throughout the house by locating the supply and returns on opposite sides of the house. The HRV fan is a particularly efficient means for providing the small ventilation air flows, with the added benefit of gaining heat recovery in the process

Provision is also made for point source pollutant control. Exhaust fans located in the bathrooms and kitchen are used to remove the localized odors and higher humidity levels created in these areas.

Filtration

It is generally considered good practice to provide for some filtration of the distributed air in the house. In the case of a house with a Heat Recovery Ventilator, a small filter could be installed in the system for the inlet air. Some HRV’s are designed to re-circ and filter house air, though their power use tends to be higher than a simple ‘once-through’ model. Higher levels of filtration generally require larger fan sizes than are found in HRV’s.

Domestic Hot Water

The base system for domestic hot water would be direct heating of the domestic water using the oil water heater. In this way, the firing rate of the appliance leads to the higher efficiency for hot water. However, some building codes don’t allow using potable water in the house heating system, in which case an indirect tank water heater similar to Amtrol Boiler Mate or Heat Transfer Products SuperStor tank could be added in a parallel zoned system through the boiler. While there is some loss of efficiency on the hot water side of things, since the boiler is within the conditioned space, and the need for heating is an overwhelmingly large part of the year, most ‘stand-by’ losses directly offset heating needs, and are not actually losses.

A well designed hot water distribution system minimizes the length of pipe runs to the various faucets, to provide shorter wait times for hot water, and less wasted heating of water that will cool in the pipework.

Energy Model Results

The results of the mechanical systems upgrades represented a reduction in energy consumption of 6.3% when compared to the energy consumption of the Building America Benchmark house design.