This article considers current trends and challenges in qualitative analysis. The focus is not on classification methods per se, but rather on their general features, such as the way the classification results are presented (hard or soft classification), or how the method is applied (single-class or multi-class). We put forward the main problems, which have not yet been fully investigated and, therefore, require special attention. Such problems include definitions of the main figures of merit in cases of multi-class, one-class, and soft and hard classifications; optimization methods in cases of rigorous and compliant approaches to classification; well-known validation methods such as (test set and cross-validation), as well as a recently introduced Procrustes cross-validation. At each point, we focus on novel ideas and methods, some of which have not yet been fully investigated and tested in practice. We believe that they can create new trends in qualitative analysis and, therefore, deserve to be discussed.

本文考虑了定性分析的当前趋势和挑战。重点不在于分类方法本身，而是它们的一般特征，例如分类结果的呈现方式（硬分类或软分类），或者方法的应用方式（单类或多类）。我们提出的主要问题尚未得到充分研究，因此需要特别注意。此类问题包括多类、一类和软硬分类情况下的主要品质因数的定义；在严格且合规的分类方法的情况下的优化方法；众所周知的验证方法，例如（测试集和交叉验证），以及最近引入的 Procrustes 交叉验证。在每一点上，我们都专注于新颖的想法和方法，其中一些尚未在实践中得到充分研究和测试。我们相信他们可以在定性分析中创造新的趋势，