Researchers in Japan and The Netherlands have, for the first time, used machine learning techniques, in particular artificial neural networks (ANNs), to predict the Indian Ocean Dipole (IOD), a positive phase of which has affected weather and climate in India and Australia in a spectacular fashion so far in 2019-20. The IOD has both positive and negative phases, and signals large socio-economic impacts on many countries and hence predicting the IOD well in advance will benefit the affected societies, note authors JV Ratnam and Swadhin K Behera (Application Laboratory, Japan Agency for Marine-Earth Science and Technology, Yokohama) and HA Dijkstra (Institute for Marine and Atmospheric Research Utrecht, Utrecht University in The Netherlands) in a paper published by Nature. The IOD is a mode of climate variability observed in the Indian Ocean sea surface temperature anomalies with one pole in Sumatra (Indonesia) and the other near East Africa. Therefore, the IOD is represented by an index derived from the gradient between the western equatorial Indian Ocean and the south-eastern equatorial Indian Ocean. It starts sometime in May-June, peaks in September-October and ends in November (2019's rather strong positive phase of the IOD lasted into early January of 2020).

Learning rates in stochastic neural network training are currently determined a priori to training, using expensive manual or automated iterative tuning. This study proposes gradient-only line searches to resolve the learning rate for neural network training algorithms. Stochastic sub-sampling during training decreases computational cost and allows the optimization algorithms to progress over local minima. However, it also results in discontinuous cost functions. Minimization line searches are not effective in this context, as they use a vanishing derivative (first order optimality condition), which often do not exist in a discontinuous cost function and therefore converge to discontinuities as opposed to minima from the data trends. Instead, we base candidate solutions along a search direction purely on gradient information, in particular by a directional derivative sign change from negative to positive (a Non-negative Associative Gradient Projection Point (NN- GPP)). Only considering a sign change from negative to positive always indicates a minimum, thus NN-GPPs contain second order information. Conversely, a vanishing gradient is purely a first order condition, which may indicate a minimum, maximum or saddle point. This insight allows the learning rate of an algorithm to be reliably resolved as the step size along a search direction, increasing convergence performance and eliminating an otherwise expensive hyperparameter.

DUBAI, UNITED ARAB EMIRATES – A flurry of diplomatic visits and meetings crisscrossing the Persian Gulf have driven urgent efforts in recent days to defuse the possibility of all-out war after the U.S. killed Iran's top military commander. Global leaders and top diplomats are repeating the mantra of "de-escalation" and "dialog," yet none has publicly laid out a path to achieving either. The United States and Iran have said they do not want war, but fears have grown that the crisis could spin out of Tehran's or Washington's control. Tensions have careened from one crisis to another since President Donald Trump withdrew the U.S. from Iran's nuclear deal with world powers. The U.S. drone strike that killed Revolutionary Guard Gen. Qassem Soleimani and a senior Iraqi militia leader in Baghdad on Jan. 3 was seen as a major provocation.

DUBAI, UNITED ARAB EMIRATES – Iran's acknowledgement that it shot down a Ukrainian airliner, killing 176 people, raises new challenges for the Islamic Republic both externally amid tensions with the U.S. and internally as it deals with growing discontent from its people. The country did itself no favors by having its air-crash investigators, government officials and diplomats deny for days that a missile downed the flight, though a commander said Saturday that he had raised that possibility to his superiors as early as Wednesday, the day of the crash. While its paramilitary Revolutionary Guard took responsibility, the same commander claimed it warned Tehran to close off its airspace amid fears of U.S. retaliation over Iran launching ballistic missiles at Iraqi bases housing U.S. forces. That retaliation never came, but the worries proved to be enough to allegedly scare a missile battery into opening fire on the Boeing 737 operated by Ukrainian International Airlines. Wider tensions between Iran and the U.S., inflamed after Iran's top general was killed in Iraq by a U.S. drone strike on Jan. 3, have for the moment calmed. However, President Donald Trump vowed to impose new sanctions on Tehran and on Friday, his administration targeted Iran's metals industry, a major employer.

WASHINGTON – U.S. officials said Thursday it was "highly likely" that an Iranian anti-aircraft missile downed a Ukrainian jetliner late Tuesday, killing all 176 people on board. They suggested it could well have been a mistake. The crash came just a few hours after Iran launched a ballistic missile attack against Iraqi military bases housing U.S. troops amid a confrontation with Washington over the U.S. drone strike that killed an Iranian Revolutionary Guard general last week. Two U.S. officials, speaking on the condition of anonymity to discuss sensitive intelligence, said they had no certain knowledge of Iranian intent. But they said the airliner could have been mistaken for a threat.

DUBAI, UNITED ARAB EMIRATES – Iran's launching of more than a dozen missiles at American-led forces in Iraq on Wednesday came after years of preparing for a confrontation with its superpower foe, whose forces are vastly larger and more advanced. The Persian Gulf country has more than 500,000 active-duty personnel, including 125,000 members of its elite Revolutionary Guard, according to a report last year by the International Institute for Strategic Studies. But international sanctions and restrictions on arms imports have made it hard for Iran to develop or buy more sophisticated weaponry. To compensate for the imbalance, Iran has developed "asymmetric" responses -- ballistic missiles, deadly drones and a web of militia allies in Iraq, Syria, Lebanon and Yemen, among other things -- with the aim of being able to inflict pain while avoiding the traditional battlefield. "From a conventional military perspective, they would get absolutely hammered," said a British former military commander who asked not to be identified because of the sensitivity of the matter.

TEHRAN – Supreme Leader Ayatollah Ali Khamenei wept Monday over the casket of a top general killed last week in a U.S. airstrike, his prayers joining the wails of mourners who flooded the streets of Tehran demanding retaliation against America for a slaying that has drastically raised tensions across the Middle East. The Tehran funeral for Revolutionary Guard Gen. Qassem Soleimani drew a crowd said by police to be in the millions, filling thoroughfares and side streets as far as the eye could see. Although there was no independent estimate, aerial footage and journalists suggested a turnout of at least 1 million, and the throngs were visible on satellite images of Tehran taken Monday. Authorities later brought his remains and those of the others to Iran's holy city of Qom, where another massive crowd turned out. The outpouring of grief was an unprecedented honor for a man viewed by Iranians as a national hero for his work leading the Guard's expeditionary Quds Force.

The American drone attack that killed Iranian Gen. Qassem Soleimani last week is the latest move in a low-level war between Iran and the U.S. that has been waged with varying degrees of intensity for over 40 years – and is likely to continue long into the future. Some people fear that recent events will escalate the long conflict into a costly all-out war between the two countries. Others may welcome what they see as the necessary and inevitable showdown leading ultimately to regime change in Tehran. The killing of Soleimani – the most prominent military figure in Iran and close to Supreme Leader Ayatollah Ali Khamenei – can be seen as an escalation and will almost certainly provoke Iranian retaliation. President Trump's boast of ordering the killing of Soleimani may further increase pressure on Iran to respond.

WhiteFox Defense Strategic Advisor and drone expert Brett Velicovich discusses the operation and mission of the airstrike that hit General Qassem Soleimani. You only get "one shot" while taking down a target like Iranian General Qassem Soleimani, drone expert Brett Velicovich said Saturday. Appearing on "America's News HQ: Weekend" with host Ed Henry, Velicovich -- who once tracked Soleimani's movements -- said that the drone strike on Soleimani was a " forceful reminder that the Iranians can no longer attack Americans with impunity, [as well as] that the U.S. government can retaliate with a wide variety of options that are both devastating actions that are short of war." "Thanks to President Trump's decisive action, we are able to use one of the tools within the government's arsenal to strike and to strike Soleimani with precision," he added. The MQ-9 Reaper drone was used to strike Soleimani early Friday at the Baghdad International Airport. With a range of 1,150 miles and the ability to fly at altitudes of 50,000 feet, the Reaper weighs almost 5,000 pounds.