乔，你像是海鸥：强舰难以约束、喜欢狂风暴雨，远远飞向大海，自得其乐。
You are the gull, Jo, strong and wild, fond of the storm and the wind, flying far out to sea, and happy all alone.
即使这些条件在实践中都难以实现，但有财政约束往往总比没有任何规则要好。
Even if these conditions are hard to meet in practice, fiscal constraints are often more useful than no rules at all.
因为开发人员通常会依赖数据库的约束，所以生成的表可能非常难以处理。
The resulting table may prove very difficult to work with, since developers typically rely on database constraints.
XSLT的使用越来越难以设置，尤其是随着浏览器的现代版本在 XSLT 的使用上放置的安全约束越来越多（参见参考资料中的链接）。
Use of XSLT is more difficult to set up, especially as modern releases of browsers increasingly place security restrictions (see Resources for a link) on the use of XSLT.
Flex和AIR有许多可能提高之处，但是许多现有的约束是必要的而且非常难以克服的，所以单纯的愿望是没有意义的。
There are a number of possible improvements to Flex and AIR, but many of the constraints are necessary and would be very difficult to overcome, so wishing would be pointless.
训练你自己健康地饮食可能需要很多的约束和大量时间，不过不管是为你的短期目标也好长期目标也好，这样是值得的，而且令人难以置信。
It may take a lot of discipline and time to train yourself to eat well but it's incredibly worthwhile for your short term and long term goals.
自然通风和日晒可以达到食品干燥的目的，但受自然条件约束，且食品卫生难以保证。
Natural ventilation and sun dried food can reach the objective, but constrained by natural conditions, and it is difficult to ensure food hygiene.
故用传统的数学优化算法，难以解决多目标、多约束问题。
So the traditional optimize algorithms is difficult to solve poly-goal, poly-restrain problems.
输入输出受限非线性系统的预测控制问题，可以看作是一个难以直接求解的约束非线性优化问题。
Predictive control algorithms for a multivariable nonlinear system with limited inputs and outputs can be formulated as a constrained nonlinear optimization problem which is hard to solve.
当线性规划约束条件的右端向量在一定范围内变化时，目标函数的最优值是右端向量的一个复杂的分片线性函数，但通常难以给出分析表达式。
The optimal objective value is a complicated piecewise linear function of the right-hand-side vector of the constraints, and its analytical expression is normally hard to obtain.
晚清洋务运动时期股份制企业的股东，难以借助企业内部治理机构充分行使对企业经理层的约束权、监督权。
In the period of westernization movement, the Stockholders couldn't fully exert their right about restraining and supervising managers by the inside administering organization of enterprises.
配电网络重构是在满足各种运行约束条件下，以网损最小或供电可靠性最高为目标，它是一个典型的非线性整数组合优化问题，常规的数学优化方法难以求解。
The purpose of distribution network reconfiguration is to obtain the minimum network loss and the maximum reliability while meeting all kinds of operational restrictions.
没有经过一定的约束的人是难以体会自由的美好的。
One does not experience the joy of freedom fully without enduring a certain extent of discipline.
同居让一段难以有进展的关系又多了一层约束力。
When you cohabit, it adds a sense of commitment to a relationship that is going nowhere.
由于该类问题不仅包含了相互冲突的多个目标函数，而且目标函数或者约束又具有不确定性，因而使得传统优化方法难以适用。
Since they often contain multiple objectives with conflict as well as uncertain objective functions and constraints, it is difficult for traditional optimization algorithms to solve them.
由于该类问题不仅包含了相互冲突的多个目标函数，而且目标函数或者约束又具有不确定性，因而使得传统优化方法难以适用。
Since they often contain multiple objectives with conflict as well as uncertain objective functions and constraints, it is difficult for traditional optimization algorithms to solve them.
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